ISSN 0494-7304 1024-4441 A R T U Ü L I K O O L I TOIMETISED СТА ET COMMENTATIONES UNIVERSITATIS TARTUENSIS 976 BIOLOGICAL AND PEDAGOGICAL PROBLEMS OF PHYSICAL EDUCATION AND SPORT Töid kehakultuuri alalt T A R T U 1 9 9 5 TARTU ÜLIKOOLI TOIMETISED ACTA ET COMMENTAHONES UNTVERSITATIS TARTUENSIS ALUSTATUD 1893. a. VIHIK 976 BIOLOGICAL AND PEDAGOGICAL PROBLEMS OF PHYSICAL EDUCATION AND SPORT V Töid kehakultuuri alalt TARTU 1995 Editorial board: Т. Jürimäe, A. Nurmekivi, A. Viru, M. Pääsuke Editor: Т. Jürimäe ©Tartu Ülikool, 1995 Tartu Ülikooli Kirjastuse trükikoda Tiigi 78, EE2400 Tartu Tellimus nr. 55. CONTENTS Brodle, D. A., Moscrip, V J. Estimation of percentage body fat by three different methods 5 Brodle, D. A., Enright, S. The prediction of residual volume from lung function and anthropometry •. j ..... 12 Amis, V. The role of strength training in enhancing the perfor­ mance capacity of sprinters (swimmers) 17 Agboiyinmi, A. P, Anthropometric determination of nutritional status of primary school children in Nigeria 31 Agboiyinmi, A. P. The relationship between calf and thigh girths and leg mechanical power in primary school children 40 Zhao Shunlai, Luo Honglu. On the threshold value of the phys­ iological load of physical education courses in colleges and universities 46 Sui Lu. Study and analysis of electroencephalograms of college students who are on different sports training levels 50 Raudsepp, L. Modeling and motor learning. A mini review ... 53 Rehand, M. Effect of aerobic exercises on body composition, blood lipoproteins and working capacity in relation to the insulin level in blood 59 Raudsepp, L., Pääsuke, M. The kinematics of running and over­ hand throwing in 8-year-old children 71 Viru, A. Restoration of normal functional activities after exercise 76 Litvinova, L., Viru, A. Studies on interrelation between blood lactate and urea responses to exercises 100 Viru, A. Fleisch pulszeitschreiber: an effective methodological principle. Significance for exercise physiology 107 Loko, J., Sikkut, Т., Aule, R, Sensitive peridds of physical devel­ opment Л. .... 121 Linkberg, R. Carriage on the period of pregnancy 127 Alev, M., Toritsõn, P. On the influence of the thickness of the wax layer on the slipping characteristics of a ski 134 3 Pihl, E., Jürimäe, Т., Kaasik, Т. Physical working capacity and blood lipid and lipoprotein concentrations in young and middle-aged women with different physical activity 141 Hein, V, Jürimäe, Т., Pihl, E. The blood lipid and lipoprotein concentrations and flexibility 146 Volver, A. A pilot study of interrelations between growth, fitness development and sexual maturation in 10 to 14 year old girls 150 Grimovas, A., Poderys, J. Peculiarities of peripheral and system­ atic blood circulation at local static work 159 Nurmekivi, A., Lemberg, H. Factors influencing the competition result and functional preparation structure in different run­ ning distances 168 Brodie, D. A., Burl, M. M. Cost versus accuracy: an examination of the reliability of three skinfold calipers 175 Brodie, D. A., Hammond, J., Slade, P. D. Knowledge of blood cholesterol within an inner city community 180 Kums, T. About the possibilities to determine reaction of connec­ tive tissue's structures in the locomotive apparatus in gym­ nasts 186 4 ESTIMATION OF PERCENTAGE BODY FAT BY THREE DIFFERENT METHODS D. A. Brodie, \. J. Moscrip School of Health Sciences, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX, United Kingdom Abstract The purpose of this study was: (i) to assess body fat using three different body composition procedures — the Bodystat 500 anal­ yser (BS) and estimates of body fat from the skinfold equations of Durnin and Womersley (DW) [5] and Jackson and Pollock (JP) [7]; (ii) to assess whether the resistance index (RI = height2/resistance) was a significant predictor of fat free mass (FFM). The subjects were 10 young males, mean age 23.4 (2.01) years, mean height 182.9 (1.9) cm and mean mass 87.4 (5.6) kg. Percentage body fat and FFM predicted from the Bodystat analyser were compared with predicted values from the two skinfold equations. The correlations obtained were: BS % fat: DW % fat, r = 0.99, BS % fat: JP % fat, r = 0.98; DW % fat: JP % fat, r = 0.98; BSFFM: DWFFM, r = 0.97; BSFFM: JPFFM, r = 0.99; DWFFM: JPFFM, r = 0.96. Analysis of variance showed there to be no statistical differences (p < 0.01) between any of the % fat content values. The correlation co-efficients between RI and % fat and FFM were RI: BS % fat, r = 0.63; RI: DW % fat, r = 0.57; RI: JP % fat, r = 0.56; RI: BSFFM, r = 0.57; RI: DWFFM, r = 0.26; RI JPFFM, r = 0.28. None of these correlations were significant at p < 0.01 level. It was concluded that estimates of body fat and FFM obtained from the Bodystat analyser were as accurate as estimates from the skinfold equations of Durnin and Womersley [5] and Jackson and Pollock [7] but that RI was not a suitable predictor of FFM in young athletic men. Introduction Methods of assessing body composition are generally divided into two categories, direct and indirect. The former category is achieved 5 by the dissection of human cadavers and animals. Only a limited number of such measurements have been made [2, 12]. Indirect methods are non-invasive techniques used to provide suitably accu­ rate estimates of body composition. The main estabUshed methods of assessing body composition melude the technique of hydrostatic weighing which was first used by Behnke [1] in 1942. It is regarded as one of the more accurate and reliable methods of body fat content assessment, even though it is inconvenient to perform for those who lack water confidence. Other methods include gamma ray spectrom­ etry, total body water by isotope or solute dilution and whole body potassium measured from potassium 40. The main disadvantage of these techniques is that they need to be performed in the laboratory situation. Anthropometric methods using weight and height ratios or various combinations of skinfolds, circumferences and diameter mea­ surements are the methods that are more typically used in the field situation to assess body composition. A relatively new body composi­ tion assessment technique that may also be used in the field situation is that of bioelectrical impedance analysis (BIA). BIA was first re­ ported in 1909 by Cremer [19] who measured impedance in biological specimens. Mann [11] in 1937 reported non-invasive measurements in humans with the work of Thomassett [18] in the 1960s establishing the basic principles of BIA. The clinical support to substantiate these principles was provided by Nyboer [13, 14] in 1970 and 1972. The BIA method simply requires the placement of four electrodes on the subject at specified locations and is therefore simple and quick to use compared to some of the other established methods. BIA is based on the bioelectrical properties of the human body with impedance measures used to detect changes in various physiological functions. The basic principle of body impedance is based on the concept that electrical flow is conducted better through hydrated fat free tissue and extracellular water compared with fat tissue due to the greater electrolyte content and thus lower electrical resistance. As a result of this impedance is directly related to levels of body fat. The greater the fat content the greater the resistance. There have been many studies that have investigated bioelectrical impedance analysis as a useful method of estimating body composition in adults, [4,10, 15, 16,19]. The first commercially available instru­ ment (the RJL system) was used to assess fat free mass (FFM) by densitometry and whole body resistance procedures by Lukaski et al [10] in 1986 and Segal et al [16] in 1985. Both studies showed high­ ly significant relationships between FFM and whole body resistive index (RI). RI is height2 divided by resistance with correlation coef­ ficients of r = 0.98 by Lukaski [10] and r = 0.94 by Segal [17] having been produced with FFM. It has been shown that resistance and height2 used separately [17, 6 20] or expressed as RI [6,10,17] have higher correlation coefficients than impedance, reactance, age, sex, body mass and body mass index. Lukaski et al [10] validated the relationship between RI and densito- metrically determined FFM. They showed RI to be a valid and reliable predictor of FFM in both men (r = 0.97) and women (r = 0.95). Van Loan et al [20] also showed RI to be strongly correlated with FFM (r = 0.97). The purpose of this study was to: (i) to investigate BIA in the estimation of percent fat, and FFM compared with estimates from the equations of Durnin and Wormersley [5] and Jackson and Pollock [7] which use skinfold measurements to estimate body density and (ii) to assess whether the RI would be a significant predictor of FFM in a male athletic population. Method The subjects in the study were 10 healthy males from various tennis clubs in the North West of England. The mean subject characteristics are presented in Table 1. Total body resistance and reactance were measured with a four terminal portable RJL impedance analyser (BIA 103, RJL Systems, Detroit, Michigan), which transmitted a current of 50khz at 800mA from the surface electrode. A Bodystat 500 analyser (Bodystat, Douglas, Isle of Man) and software was also used to estimate percentage fat and FFM on each subject. The above two techniques were performed with the subjects in the supine position with their limbs abducted from the body ensuring that the limbs were not in contact with the trunk. The current electrodes were places on the ventral surface of the right hand and foot just above the knuckles and below the toes. The detector electrodes were placed midway between the radial and ulna styloid processes of the right hand and the medial and lateral malleoli of the right ankle. Five resistance and reactance measurements were taken for each subject and the mean of the five measurements used as the representative value. Skinfold measurements were taken using Holtain skinfold cahpers. The sites were the triceps, biceps, subscapular, suprailiac, abdomen, chest and anterior thigh as described by Lohman et al [9]. Two mea­ surements were taken at each site and the mean of the two used as the representative value. All measurements were taken on the right side of the body. The skinfold measurements were used to predict body density using the equations of Durnin and Womersley [5] and Jackson and Pollock [7]. Using these body density values percentage body fat, 7 fat free mass and fat mass were then calculated. Percentage body fat was calculated as a percentage of body mass using the formula of Brozek et al [3]. The data were analysed using the Superstate statistical package involving descriptive statistics, Pearson product moment correlations, analysis of variance, and Student's T tests. Percentage body fat and FFM estimated by BIA were compared with the values estimated by the equations of Durnin and Womersley [5] and Jackson and Pol­ lock [7]. Results The means and standard deviations for age, mass, height, electrical impedance and estimated percentage fat, FFM and FM values are given in Table 1. T a b l e 1 Means and standard deviations for anthropometric measurements Mean SD Age (years) 23.4 2.0 Mass (kg) 87.4 5.6 Height (cm) 182.9 1.9 RJL resistance value 456.6 23.6 RJL reactance value 62.1 4.7 Resistance index 68.8 6.5 Bodystat % fat 16.1 1.5 Bodystat fat mass 14.2 2.2 Bodystat fat free mass 72.2 3.7 Durnin & Womersley % fat 16.5 1.6 Durnin & Womersley FM 14.4 4.9 Durnin & Womersley FFM 72.7 3.5 Jackson & Pollock % fat 16.9 1.6 Jackson & Pollock FM 14.8 2.3 Jackson & Pollock FFM 72.6 3.7 RJL impedance 460.0 23.2 The correlation between the three different methods of calculating percentage body fat and fat free mass are shown in Table 2. Analysis of variance showed there to be a non significant different (F = 0.71) between the three methods as would be expected from the mean values in Table 1. 8 T a b l e 2 Correlation between methods of measuring body fat Method r p < Bodystat % fat: Durnin & Womersley % fat 0.99 0.001 Bodystat % fat: Jackson & Pollock % fat 0.98 0.001 Durnin & Womersley % fat: Jackson & Pollock % fat 0.98 0.001 Bodystat FFM: Durnin & Womersley FFM 0.97 0.001 Bodystat FFM: Jackson & Pollock FFM 0.99 0.001 Durnin & Womersley FFM: Jackson & Pollock FFM 0.96 0.001 T a b l e 3 Correlations between RI, % body fat and FFM Methods r RI: Bodystat % fat 0.63 RI: Durnin and Womersley % fat 0.57 RI: Jackson and Pollock % fat 0.56 RI: Bodystat FFM 0.57 RI: Durnin and Womersley FFM 0.26 RI: Jackson and Pollock FFM 0.28 The correlations between the resistance index and percentage body fat and FFM are shown in Table 3. At p < 0.01 (critical value 0.66) there were no significant correlations between the RI and % fat or FFM by any of the methods. Discussion The lack of statistically significant differences between the three methods of estimating percentage body fat showed that the Bodys­ tat 500 analyser is as valid as the skinfold measurement of Durnin and Womersley [5] and Jackson and Pollock [7]. It is accepted that this study is based on a small sample size, but their homogeneity gives more credibility to the statistics. The advantage of the Bodys­ tat 500 analyser could be for more heterogeneous samples, especially those containing individuals whose skinfold measures are difficult to measure. This applies to the Durnin and Womersley [5] equation when obese individuals are difficult to measure because of caliper slippage and to the Jackson and Pollock [7] equation when the thigh reading of muscular individuals is also difficult to establish with ac­ curacy. The reliability of the Bodystat 500 has been established as 2 9 satisfactory by Jurimae and Juriso [8]. The Bodystat 500 analyser can therefore be used as an alternative, reliable method for the predic­ tion of percentage fat and FFM in healthy people of mid range BMI (21-26). The RI in this study was not a good predictor of either percent­ age body fat or FFM, yielding non significant correlations. As RI is based on resistance and height squared, it emphasizes the importance of the conductor length in the estimation of body fat or FFM from electrical methods. It is hardly surprising that RI: Bodystat % fat almost reached the critical level for significance (r = 0.63 as opposed to the critical level of 0.66 at p < 0.01) as the formula used to calculate % fat would include resistance and height. Reactance is commonly measured in addition to resistance and impedance is then calculat­ ed from the formula: impedance = the square root of [resistance squared + reactance squared]. It was an interesting observation that the impedance values for the Bodystat averaged at 426 ohms, where­ as for the RJL the average was 460 ohms. A T-test on these values indicated a significant difference between the impedance values yet when converted to percentage body fat or FFM values, the differences were non-significant. Having confirmed with the manufacturer that the Bodystat values are impedance and not resistance, (and stated in print by Maughan, [12]), we conclude that the formulae to predict the body fat and FFM values are different between manufacturers. Although RI as a simple index to estimate body fat or FFM has not in this study supported the work of Lukaski et al [10], it is recognized that the small sample size may be a contributing factor. Critics of electrical impedance methodology tend to have available alternative and expensive options such as neutron activation or bone densitome­ ters. In the quest for a low cost, non-invasive, transportable, ethical, field method for epidemiological use, this study gives further support to bioelectrical impedance as a viable option. REFERENCES 1. Behnke, A. R., Feen, В. G., Welham, W. C. The specific gravity of health men: body weight -=- volume as an index of obesity. — JAMA, 1942,118, 495-501. 2. Brodie, D. A. Techniques of measurement of body composition. — Sports Med., 1988, 5,1W0 and 5,74-98. 3. Brozek, J., Grande, R., Anderson, J. T„ Key, A. Densitometrie analysis of body composition: revision of some quantitative assumptions. — Ann. NY Acad. Science, 1963,110:113-140. 4. Coxon, A. ¥., Kreitzman, S. N.,M organ, W. D., Johnson, P. G., Eston, R. G., Howard, A. N. Change in body composition and energy balance on VLCD: A multicentre study. — Am. J. Clin. Nutr., 1992, 56,303S. 10 5. Durnin, J. V. G. A., Womersley, J. Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged 16-72 years. — Br. J. Nutr., 1974,32,77-92. 6. Houtkooper, L. В., Lehman, T. G., Going, S. В., Hall, M. C. Validity of bioelectrical impedance for body composition assessment in children. — J. Appl. Physiol., 1989, 66, 814-821. 7. Jackson, A. S., Pollock, M. L. Steps towards the development of general­ ized equations for predicting body composition of adults. —C an. J. Appl. Sports Sei., 1982, 7,189-196. 8. Jürimäe, Т. Jüriso, R The reliability of different methods of body compo­ sition measurement in female University students. —Acta et Commenta- tiones Universitatis Tartuensis, 967: Biological and Pedagogical Problems of Physical Education and Sport IV, 1994,42-48. 9. Lohman, T. G., Slaughter, M. H., Selinger, A., Boileau, R. A. Relationship of body composition to somatotype in college age men. — Hum. Biol., 1978,5,147-149. 10. Lukaski, H. C., Johnson, E E.. Bolunchuk, W. W.. Lykken, G. 1. Assessment of fat free mass using bioelectrical impedance method to assess human body composition. — J. Appl. Physiol., 1986, 60,1327-1332. 11. Mann, H. Study of peripheral circulation by means of an alternating current bridge. Proceedings for the Society for Experimental Biology and Medicine, 1937, 36, 670. 12. Maughan, R. J. An evaluation of a bioelectrical impedance analyser for the estimation of body fat content. — Br. J. Sports Med., 1993,27,63-66. 13. Nyboer, J. Electrical Impedance Plethysmography. 2nd edition. CC Thomas, Springfield, 1970. 14. Nyboer, J. Workable volume and flow concepts of bio-segments by electri­ cal impedance plethysmography. — ИТ Journal of Life Sciences, 1972, 2,1-13. 15. Ross, R., Leger, L., Martin, P., Roy, R. Sensitivity of bioelectrical impedance to detect changes in human body composition. — J. Appl. Physiol., 1989,67,1643-1648. 16. Segal, K. R, Gutin, В., Prosta, E., Wang, J., Van Itallie, Т. В. Estimation of human body composition by electrical impedance methods: A compar­ ative study. —J. Appl. Physiol., 1985, 58:1565-1571, 17. Segal, K. R., Van Loan, M., Fitzgerald, P. I., Hodgdon, J. A., Van Ital­ lie, Т. B. Lean body mass estimation by bioelectrical impedance analysis: A four site cross-validation study. — Am. J. Clin. Nutr., 1988,47, 7-14. 18. Thomassett, A. Bioelectrical properties of tissues. Lion Medical, 1936, 209,1325-1352. 19. Van Loan, M. D., Mayclin, P Bioelectrical impedance analysis: Is it a reliable estimator of lean body mass and total body water? — Hum. Biol., 1987, 59, 299-309. 20. Van Loan, M. D., Boileau, R A., Slaughter, M. H„ Stillman, R J., Loh­ man, T. G. Association of bioelectrical resistance with estimates of fat free mass determined by densitometry and hydrometry. — Am. J. Human Biol., 1990, 2,219-226. 2* 11 THE PREDICTION OF RESIDUAL VOLUME FROM LUNG FUNCTION AND ANTHROPOMETRY D. A. Brodie, S. Enright Department of Movement Science, University of Liverpool, UK and Department of Physiotherapy, University of Brighton, UK Abstract The purpose of this study was to examine whether lung function and anthropometric measures will predict residual volume by the criterion method of gas dilution. A Pearson product moment correlation coefficient was under­ taken using three lung function indices and three anthropometric measurements as the predictor variables. A strong positive cor­ relation was revealed for two indices of lung function, FEVi and TLC (r = 0.74, p < 0.01 for both). A positive correlation was also obtained for vital capacity (r = 0.58, p < 0.05). Examination of the anthropometric methods showed non sig­ nificant correlations with the criterion measurement of residual volume. The result obtained from this study would suggest that anthro­ pometric measurement will not suffice in the prediction of residual volume but that lung function indices are a valid and useful method of prediction, particularly FEVi which can be measured by use of a simple spirometer. Introduction Accurate determination of the changes in the static lung volumes can be obtained by the use of an air displacement spirometer. Howev­ er some gas remains in the lung after a maximal expiration, this is the residual volume (RV). The volume of gas in the lungs after a normal expiration is the functional residual capacity (PRC). Neither PRC or RV can be measured with a simple spirometer. However, various gas dilution techniques can be used, the helium dilution technique being the most widely used in clinical situations. The measurement of the total lung capacity and its subdivisions, 10 including the FRC and the RV by the closed circuit helium dilution method requires 20 minutes of the subject's time yielding values which are reproducible to within ± 200 ml [1]. Other less time consuming methods are available as a method of predicting the residual volume. A nomogram which relates indices of lung function to stature and age for both male and female subjects is available [1]. This method is believed to be acceptable as both the FRC and RV show relatively little variation between individuals of the same sex and stature in young healthy subjects [4]. However, this method is unsuitable in subjects with lung disease due to abnormal residual volume as a result of gas being trapped within obstructed airways. Methods to assess changes of the lungs with breathing can be undertaken with various anthropometric methods: height, weight, age and change in circumference of the chest wall during breathing. Although the increases in circumference observed by this method do tend to be small and hence its accuracy questionable, it is however a very simple method and requires little time. The purpose of this study was to examine the methods available for prediction of residual volume from lung function indices and anthro­ pometric measurements and to evaluate whether these predictions will predict residual volume using the criterion method of helium dilution. Method Twelve physically active women (35 ± 15 years, mass 58 ± 15 kg and height 167 ± 11 cm) volunteered to take part in this study. , Chest circumference measurements were recorded by taking the mean of three readings for full inspiration and maximal expiration in three areas; the level of the axillary fold and the level of the 8th and the 11th rib respectively. The difference between inspiration and expiration was calculated and the sum of the means of the three measurements was recorded. Lung function measurements of peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEVi) were obtained using a single-breath dry spirometer (Vitalograph Limited) and a Wright peak flow meter. Subjects were instructed to inhale maximally and follow this with a maximal expira­ tion. For these recordings of ventilatory performance, the subject was instructed to attempt three tests; the mean of the three determinations was used to provide a stable index. Other indices of lung function (vital capacity, functional residual capacity, total lung capacity and residual volume) were obtained by use of a gas dilution spirometer (PK Morgan Ltd). The subject is con­ 13 nected to a spirometer containing a known concentration of helium which is virtually insoluble in blood. After some breaths, the helium concentration in the spirometer and the lung become the same. Since no helium has been lost the amount of helium present before equili­ bration (concentration x volume) is Ci x Vj and equals the amount after equilibration C2 x (Vi + V2). From this V2 = Vi (Ci - С2УС2. In practice oxygen is added to the spirometer during equilibration to make up for that consumed by the subject and also carbon dioxide is absorbed [3]. After equilibration of the gas transfer the spirome­ ter, subjects were connected to the machine by securing their mouth around a mouthpiece and applying a nose-clip. After a period of normal breathing (tidal volume, TV) the subject was asked to breath out maximally (to residual volume, RV). The subject was then asked to breath in maximally (their vital capacity, VC). RV is calculated as functional residual capacity (FRC) — expiratory reserve (ER). Total lung capacity (TLC) is equal to RV + VC. In order to correct for internal inconsistencies in the results, firm instructions were given by the same operator. To avoid the possi­ bility of ventilatory capacity alterations all measurements were taken under the same conditions (i.e. in terms of time of day and avoiding heavy meals beforehand) and a correction factor was employed to allow for alterations in ventilatory capacities due to change in tem­ perature. Using a prediction nomogram [2] relating indices of lung function, residual volume was predicted from the three indices of lung function obtained: FEVi, VC and TLC. The peak expiratory flow rate, al­ though measured was not used as an index of ventilatory ability in this study. This was because it was demonstrated that trials were depen­ dent on the degree of expiratory effort and it was not as reproducible as the FEVi. A Pearson-product-moment correlation was performed on these three parameters against the criteria measurement of residual volume by helium dilution. Results Table 1 gives the correlation coefficients, means and standard de­ viations for the residual volumes predicted from the nomogram from the variables of FEVi, vital capacity and total lung capacity. Table 2 gives the correlation coefficients, mean and standard devi­ ations for the residual volumes predicted from height, mass and mean chest expansion. All the correlations in Table 2 are non-significant, having failed to reach the critical value for p < 0.05. 14 T a b l e 1 Correlations and means (standard deviations) for residual volume Nomogram Residual Volume Correlation Predictor Mean (SD) Coefficients P< FEV 1.15 (0.43) 0.75 0.01 VC 1.21 (0.60) 0.58 0.05 TLC 1.27 (0.41) 0.74 0.01 T a b l e 2 Correlations, means (standard deviations) for height, mass and mean chest expansion Predictor Mean (SD) Correlation Coefficient Height 1.61 (0.12) m 0.45 Mass 61.0 (7.6) kg -0.44 Chest Expansion 8.5 (1.9) cm 0.31 Discussion The high correlations obtained between the predictions of residual capacity from nomograms and the actual measurement support the opinion of Cotes et al. [1] that lung function measures can be used appropriately to predict residual volume. The merit of this is that the direct measurement of residual capacity is costly both in terms of time and operator expense. Helium dilution techniques are often only to be found in hospitals, whereas the need for residual volume may be elsewhere. This would especially apply in human performance labo­ ratories where hydrostatic weighing is used to estimate body fat. The error produced by using residual capacity predicted from a nomogram based on FEVi for estimating body fat is likely to be less than per cent. For epidemiological research this is probably acceptable. Changes to body fat caused by specific treatments may require a direct measure of residual volume to reduce errors further. It was interesting to note in Table 1 that vital capacity only predicted residual volume at p < 0.05 with a correlation (r = 0.58) which accounted for only 34 per cent of the variance. Vital capacity has been demonstrated to show larger variations with treatment and operator conditions than FEVi. This may have contributed to the poorer correlation, although on a theoretical basis it would be expected that a measure of lung volume would be more closely related to residual volume than a measure of lung power. The anthropometric measures were non-significantly correlated but as they are a further step removed from the use of lung 15 function measures to predict residual volumes this is not surprising. In most laboratories needing to estimate residual volume the equip­ ment to measure lung volumes is likely to be available. Prediction from simple anthropometric variables is valuable in field conditions when more complex equipment is unavailable. In this situation the need to estimate residual volume is less likely to be necessary and if it is required then the use of a simple flow meter such as the Wright peak flow meter would be the method of choice. It is recognized that this study is based on a relatively small sample size and of a single sex. However it does provide a basis for a more extensive study of men and women and gives further support to those experimenters who are concerned that using the prediction of resid­ ual volume is limiting their experimental validity. Those researchers who are in the fortunate position of having direct access to helium dilution or other direct methods of measuring residual volume should continue to do so. For those unable to obtain such access a predictive nomogram, with the limitations described here, will continue to be an acceptable alternative. REFERENCES 1. Cotes, J. E. Lung Function: Assessment and Application in Medicine (3rd ed.) Oxford: Blackwell, 1975. 2. Johnson, N. M. Respiratory Medicine. Oxford: Blackwell, 1986. 3. Lewis, В. M. Use of two inert gases to measure functional residual capac­ ity. — J. Appl. Physiol., 1971,31,629-931. 4. West, J. B. Pulmonary Physiology — The essentials. 2nd Edition. Balti­ more: Williams & Wilkins, 1974. 16 THE ROLE OF STRENGTH TRAINING IN ENHANCING THE PERFORMANCE CAPACITY OF SPRINTERS (SWIMMERS) V. Amis Latvian Medical Academy Department of Physical Education Brivzemnieka str. 24, Riga, LV-1004 Latvia Introduction In cyclic athletic disciplines, the athletes' results, to a large ex­ tent, depend on their performance capacity, that is, on their ability to develop high power and to maintain it for a certain period of time. To enhance the performance capacity, various methods are employed, including strength training in different ways. It is known that per­ formance capacity and the athletes' results in many sports closely correlate with the development of maximal strength and muscle cir­ cumference. Not always, however, does strength training increase performance capacity. Quite often, performance capacity and ath­ letes' results decrease in the result of intensive strength training [10, 11,13,16]. The aim of our research was to establish the effect of different strength training methods on various physiological, morphological and biomechanical characteristics and performance capacity of low- trained students and qualified athletes — swimmers. Methods In the experiment with low-trained students (31 persons aged 18-24 years) we used four methods of strength training (see Ikble 1). These methods were selected for specific aims of physiological effect. The method for the 1st group consisted of training with submaxi­ mal weights until exhaustion. Such training facilitates the increase of maximal strength and myofibrillic hypertrophy in all muscle fibers, and it enhances the energy potential — the glycogen contant and the activity of corresponding ferments mainly in the fast muscle fibers [7,15]. 3 17 T a b l e 1 Methods of strength training Experimental groups I (n = 8) II (n = 7) III (n = 7) IV (n =9) Weight (% of max.) 70-90 60-70 40-50 40-50 Repetitions 3-12 8-12 15-25 15-25 Tempo: a) maximal X b) medium x c) slow x X Series 4-10 Rest 3-5 min (between series) The method for the 2nd group employed slow, smooth move­ ments without relaxation of the muscles. Exercises were performed with 60-70% of maximal weights and were stopped before reaching exhaustion. In such exercises, mainly the slow muscle fibers are in­ volved. The muscle tension stops the blood supply of muscles [17], the result being a higher concentration of free creatine and lactate. Such conditions facilitate the hypertrophy of myofibrils mainly in the slow and the fast oxidative muscle fibers [14,18]. The 3rd group performed their strength training with 40-50% of the maximal weight, doing movements with maximal power but in a slow frequency — one movement per every 3-4 seconds. Several physiological investigations show that when very fast movements are performed with great power, mainly the fast twitch units and muscle fibers are selectively activated [11]. The 4th group performed strength training with 40-50% of the maximal weight in maximal frequency until exhaustion. This method is similar to that of the 3rd group, while the high tempo facilitates fast concentration of lactate and rapid development of fatique. Such a pattern of muscle work is characteristic for competition exercises performed with maximal power. All four groups performed two exercises: 1) bench press, and 2) imitation of swimming motion in a special devise [19] while lying on a swimming ergometer. Exercises by these methods were performed in two sessions a week for six consecutive weeks. In the following second period (three weeks) the groups' training methods were inter­ changed: the 1st and 2nd groups took up training by the initial method of the 3rd group, while the 3rd and 4th groups used now the initial method of the 1st group. The experiment with swimmers was carried out after completion of the experiment with low-trained students. In the athletes' strength 18 training, the methods of the 1st and 3rd groups were utilized which caused the gratest enhancement of performance capacity for low- trained students. Swimmers performed strength training thrice a week: two sessions by the method of the 1st group, and one ses­ sion by the 3rd group's method. The swimmers' group included two Masters of Sports, two lst-class athletes and three 2nd-class athletes (7 persons altogether, aged 18-24 years). The athletes' group differed from the low-trained students by a slightly lower mean body weight (see Table 2), greater mean chest circumference, and considerably higher maximal strength when performing the swimmer's motion imi­ tation (for 26%) and performance capacity during the 45 s test on the swimming ergometer (for 17.5%). Before the experiment and after each stage of it, the following measurements were done: body weight, circumference of the upper arm and chest, maximal strength, maximal power of one movement, performance capacity during the 30 s bench press test, performance capacity during the 45 s test on the swimming ergometer. Swimmers were additionally tested for their stroke force in water and swimming speed in 50 meter distance. The upper arm circumference measurements were taken before warm-up on a strained muscle with a tape measure, while the chest circumference measurements were taken in a relaxed state at the nip­ ple level. On the basis of these measurements, the relative muscular hypertrophy resulting from strength training was estimated. The max­ imal strength was measured by the maximal lifted weight in both exer­ cises, and the isometric strength was measured during the swimming motion imitation, lying on the swimming ergometer, with the strength dynamometer, by generally accepted methods [19]. The maximal power of one movement was measured by the method of cyclography, after M. Shakirzyanov [20], during the bench press with 50% of the maximal weight. Performance capacity during the 30 seconds test was measured with the same weight, performing the exercise in maximal tempo. For the purpose of calculating the work, only the overcoming motion was taken into account. Performance capacity during the 45 s test was measured on the swimming ergometer with the constant re­ sistance of 3 kgP, which roughly corresponds to water resistance while swimming at competition speed. Results and discussion A close positive correlation was established between: - maximal power and maximal strength, r = 0.88; - 30 s performance capacity and maximal strength, r = 0.94; 3* 19 { CS О 3 * * * -4 xh СП CS VO 00 #CS * * cd ttn tn tn tn in iсn- tn ЧО 00 On чо xr tn •inSi­ rtn-н * § I §>§"§> l->H -cHn -н 4141 С4П1 41 41Tt C- сVOп rt~n r^d-" OOSn 0401 41 ON •sf 41 0401 41 41 VO VO t> Tt" NO ON Tj- ЧCОS СOПN г- in VO rV-O tn vo VO NO r- г* 00 $ •s # # .2 ö О ON VO 0d) d) VO Tf CtnS on r~ очо чо о ON ON in in in VO ЧО СП Xf rxf-- о X) 41 -H -я 41 41 41 41 41 41 41 41 41 С IоH I Tt CS о\ СП Оо CS чо Xt- CS t-н CS О СП tn 00 "St cS r-£ СП о Он tn SO чо tn VO VO OTfnr CNOS CNOS CtnS чСоП tVnO Р # # тз I II СП VO rH tt 1СЛП •оsf tn tn tn ' 00 •T -СSПt "CSSt CS CСПS СCПS d .Bf -н-н -н 4141 1 I- C 4S1 41 41 41 O4N1 41 l> 0401 i i l Оin 1tnЛ гtn- С C tnП S оСП "t о I a tn rt~n оtn юtn txnh •xsft 0"50J* "tdn- »a # # # CS tn * т-Н СП о ON 00 J # чо r- •st NO 00 СП СП СП СП СП СП CS CS* СП CS CS cs CS CS 11 -tНn i4-<1 -н Г4-1 C4S1 •4s1t 41 ̂ 14-H1 41 41 41 С4П1 04r- 01 41 сп о in II чо tri •st СП "st СCSП* о"sf ö "St CS 00 ö С•sПr 00 СП СП xf СП rСtП rЫf CS in # # # # # * i 1 чо ОО st ON тН г- tn 00 xf 00 OS oo чо чо' VO* vd К чо tn tn tn СП СП СП •st •sh gl jj ни -н 4141 4 ̂ 41 41 41 41 41 HH 41 41 CS 00 Ох Os СП О •st о 0 0 On tn г-н К ч0о0 rH CS* Os 0I в Г- 00 00 0 CS0* Г- NO Г 0- 00 о rC»S 0C0S r̂ - 0Cг- 0S " £> Ii # # О Оч СП СП "Ч ̂ тН T-H CS СП II Ö 1-Н i-H 1-н 1-Н 1-Н 1-н 1—5 -н -н i 4141 1 4141 1 1 in 41 41 V4O1 41 Is СП 00 xh 1-4 00 p VO "=t in in VO СП rt* СП Tt СП •st Г| СП СП СП СП СП СП СП СП СП СП а Е # . •а| tn oo CS г-н "sf CS 00 tn VO 00 t—i гн СП СП 1-Н СП 1-н 1-H es CS 8,8. -i 41 41 4141 41 41 41 41 г- tn г» CS С4П1 41 m VO Г- es in sf о OONS 1-Н OЧОS O00S 0O0N OONn cn б з s Os о о о <"• 1 -н 1-Н 1-Н Ох ОО 1-н CS 00 NO 00 tn ON 1-н •rH i—l in in in tn СП СП e£s СП -н -н 1 41 41 1 41 41 1 41 41 1 41 о о s Г- ON t-н in Г-Н СП ш CS 00 £ к к in tn xt 't tfi tn to СП СП г- г- Г- r- г- r~ г- с0) С с е<0 сCD о £> о Й 0) е ,х )^ H»ю (сSС ,2а и l ö ö SЧч 2+3 *Sd I s s i I a š š - maximal power and chest circumference, r = 0,75; - maximal power and upper arm circumference, r = 0.75; - 30 s performance capacity and chest circumference, r = 0.82; - 30 s performance capacity and upper arm circumference, r = 0.80; - 30 s performance capacity and maximal power, r = 0.79. Maximal power and performance capacity (with 50% of maximal weight) correlate weakly with the maximal speed of an unresisted movement, r = 0.40 and r = 0.19 respectively. Changes in morphological indicators, maximal strength, power and performance capacity on consecutive stages of training are shown in T&ble 2. In the result of six weeks of strength training, the circumference of upper arm and chest increased significantly for individuals in the 1st, 2nd and 3rd low-trained student groups (Fig. 1). In the 4th group, changes in muscle circumference were small, for some individuals measuresyeven decreased. Changes in body weight were small in all groups, significant changes did not occur. in IV fflL AB AB AB Fig. 1. Enhancement of chest and upper arm circumference after 6 weeks of training. I-IV —experimental groups A —chest circumference В —upper arm circumference The maximal strength on the bench increased significantly for indi­ viduals in the1 st, 2nd and 3rd groups, while they increased in all groups 21 on the swimming motion imitation exercise (Fig. 2). Characteristical­ ly, strength on the swimming motion imitation exercise increased in all four groups, even for individuals whose muscle circumference did not increase. The maximal strength in this exercise was determined by the maximal weight, allowing the subject to fully complete the swim­ ming movement while staying on the swimming ergometer. Strength on this exercise increased rapidly during the first two weeks, while further enhancement was lower. This may be explained as a result of developing specific inter-muscular coordination, since before the experiment students had not performed such an exercise. In the case of the bench press exercise, however, which had been used before in the students' physical education lessons, the muscle strength started to grow only in the third... fourth week when 6-7 sets of each exercise were done. Such load was usually not utilized during the physical education lessons. Isometric strength measurements proved to be not sufficiently objective, since the strength varied considerably on one and the same day. On the contrary, differences in dynamic strength during repeated measurements usually did not exceed 1 kg. % IV 25 20 15 10 5 A В A В A В A В Fig. 2. Enhancement of maximal strength after 6 weeks of training. I-FV —experimental groups A — maximal strength on the bench press В — maximal strength on the swimming motion imitation The one-movement maximal power on the bench press, with 50% of the maximal weigth, increased in the 1st, 3rd and 4th groups (Fig. 3). The greatest power increase was established in the 3rd group (11.1%) 22 performing explosive movements alternated by 3-4 s rest intervals. For most individuals in the 2nd group, however, who did slow move­ ments without relaxing their muscles, the maximal power decreased. It might have been caused by muscles-antagonists being involved which is usual when performing slow movements under great tension. 25 III IV 20 15 rih ъ Fig. 3. Changes in maximal power of one movement on the bench press with 50% of the maximal weight after six weeks of training. I-IV —experimental groups The increase of maximal power is caused by other physiological processes. For the 1st group, the power enhancement is mainly re­ lated to muscular hypertrophy — the increased amount of myofibrils and enlargement of energy sources. In this group, the maximal power of one movement increased both with large (80%) and small (20%) weights. On the contrary, in the 4th group where muscular hypertro­ phy was small, power increased within a narrow resistance range — with 40-60% of the maximal weights — whereas with 20% and 80% power enhancement was small: in some cases the power even dimin­ ished. Consequently, power enhancement in this group is related to a special coordination between muscles which typically develops as a result of overcoming a cetrain resistance with maximal speed. Such changes have also been fixed by other researchers [10,15]. In the 3rd group, the power enhancement was facilitated both by the muscular hypertrophy and by that special inter-muscular coordination: conse­ 23 quently, the enhancement of maximal one-movement power was the greatest in this group. Performance capacity during the 30 s test on the bench press and during the 45 s test on tihe swimming ergometer increased consider­ ably in all groups (Fig. 4). It has been observed by other researchers too that training muscles with different resistance, the enhancement of performance capacity (strength endurance) in tests with average external resistance is substantial and fairly similar [1,2]. For example, nine weeks of muscle training with high weights and low maximal rep­ etition rate (6-8 repetitions), and with low weights and high repetition rate (15-20 repetitions), led to an increase of performance capacity, testing athletes with 60% resistance, for 25% and 28% correspond­ ingly [2]. The greatest enhancement of performance capacity was observed when a combined training program of both these methods was used [2]. И 1 1 1V - - - i 1 - 1 i AB AB AB AB Fig. 4. Enhancement of performance capacity. I-IV —experimental groups A — in the 30 seconds test on the bench press В — in the 45 seconds test on ergometer Another research established that as a result of training with small weights (30-40 and 100-150 repetitions), the relative muscular en­ durance substantially increased — for 22% and 28% corresponding­ ly, while the maximal strength failed to enlarge. Training with high weights and low repetition rates, however, enhanced the maximal 24 strength and also the absolute muscular endurance, while the rela­ tive muscular endurance (in a test with resistance determined in per cents of the maximal strength) did not increase [1]. In our research, the greatest enhancement of performance capacity (absolute muscu­ lar endurance) resulted in the 1st and 3rd groups. Methods used by the 2nd and 4th group were less effective. This was confirmed by the experiment's second stage when the strength training methods were inter-exchanged between the groups. On this second stage, the perfor­ mance capacity in both tests significantly increased in the 2nd and 4th groups who were now taking up the methods of the 3rd and 1st group correspondingly. On the contrary, in the 1st and 3rd groups (who also changed their methods of training) increases in performance capacity were small (Table 2). Besides, a disadvantageous summation of dif­ fering training effects was observed: in the first group, maximal power increased but performance capacity decreased, while in the 3rd group the maximal power decreased but performance capacity enhanced (see Table 2). Therefore the athlets' group was treated with these methods simultaneously (two trainings with the 1st group's method and one session with the 3rd group's method a week). The swimmers' group continued their swimming sessions during the strength training stage in various regimes with approximately the same amount of load, with the exception of aerobic load which was reduced by about 50%. The swimmers' group's sessions were arranged in such a manner that after the strength training (for at least 24 hours) no high aerobic exer­ cise followed, while after an endurance training no strength training followed within the next 24 hours. Such a session plan was based on researches having established that the effects of strength training and endurance training on the formation of new muscle tissues differ and are mutually competitive [3, 6,12, 21, 22]. As a result of endurance training the number and size of mitochondria enlarges, the activity of mitochondria and some cytoplasmic enzymes increases, and the diam­ eter of slow and oxydative-expands-glycolytic muscle fibers expands [3,6]. It is established that the adaptation of mitochondria progresses due to the specific synthesis of mitochondric proteins which is facili­ tated by metabolic and hormonal changes that develop as a result of endurance training [12, 22]. These changes sharply reduce the syn­ thesis of myofibrillic and sarcoplasmic proteins [12,21]. In their turn, metabolic and hormonal changes produced by strength training, facil­ itate the synthesis of myofibrillar proteins in glycolytic and oxidative- glycolytic muscle fibers while impeding the synthesis of mitochondral proteins. As a result, the quantity of contractive proteins increases without an adequate growth of mitochondria. In addition, the relative density of mitochondria and capillaries decreases and the production of lactate increases, which facilitates a more rapid development of fatigue [8, 9]. For these conditions, simultaneous training of muscle 4 25 strength and muscular endurance does not usually produce a growth of muscle circumference and increase of performance capacity even in low-trained individuals [4, 23]. Strength in this case may enhance due to the development of nervous coordination mechanisms, which does not produce increased power in fast movements. Max. 25 strength 20 Performance capacity Inactive force in water with arms In full coordination Swimming speed in 50 m distance legs w -5 L Fig. 5. Changes in swimmers strength, performance capacity and swimming speed after 6 weeks of training. In our experiment with swimmer-sprinters the main purpose was to establish the effect of sustained strength training on the athletes' special performance capacity. However, it would be inappropriate to exclude aerobic load altogether, since even in the shortest swim­ ming distance (50 m) which can be made in no less than 20 seconds, aerobic energetics and aerobic performance capacity play a signifi­ cant role [5, 11, 15]. The training program used in our experiment was intended to significantly enhance muscle circumference, strength and maximal power, while maintaining aerobic capacity on the lev­ el attained before. By using this combined method in the course of six weeks, the muscle circumference significantly increased (Table 2), as well as the maximal strength, performance capacity and the stroke force in water when swimming only with the help of arms (Fig. 5). The tractive force of legs slightly decreased, but it increased for 5.8% when swimming in full coordination. Nevertheless, swimming speed in the 50 m distance was lower than before the strength training. This can be explained by a weakening of coordination, swimming technique and 26 the feeling of water. Swimming speed rapidly increased again, howev­ er, after suspending strength training, when most athletes surpassed their personal records. These athletes whose muscle circumference, maximal strength and performance capacity had enhanced compar­ atively, showed smaller increase of speed, and they did not surpass their personal records. Masters of Sports had their strength train­ ing suspended 17 days before competition while their performance capacity on the ergometer was tested on the next day after compe­ tition. Fig. 6 shows the dynamics of maximal strength, performance capacity (on ergometer) and swimming speed (in 50 m distance) for two Masters of Sports after six weeks of strength training and three weeks after suspending strength training. The athlete A's muscle cir­ cumference, maximal speed and performance capacity significantly enhanced. After he suspended strength training, his swimming speed rapidly increased, and he surpassed his personal records in the dis­ tances of 50, 100 and 200 m. The athlete B, however, fell ill at the beginning of the strength training stage, and consequently his maxi­ mal strength and performance capacity enhanced less and three weeks after suspending strength training decreased to the former level. The athlete B's results in competition were below his personal record. Performance capaaty Swimming «pcedm 50m distinct -5 L Fig. 6. Changes in maximal strength, performance capacity and swimming speed for the Masters of Sports A and B. Open bars — changes after six weeks of strength training Striped bars — changes in 3 weeks after suspending strength training 4* 27 . - • ~ I1 Three weeks after suspending strength training and notwithstand­ ing very high swimming load (II sessions per week), the muscle circum­ ference, maximal strength and performance capacity fell significantly while swimming speed enhanced (Fig. 6). Athletes of lower qualifications did not take part in competition. After six weeks of sustained strength training, the athletes continued strength training once a week and had swimming training three times a week. In the first week after warm-up, the athletes used mainly anaerobic lactate loads: 3 x (4 x 50 m) in maximal speed, where the interval between sets was 3, 2,1 min long, and the interval between series was 10 min long. In the second week they used mainly aerobic load: 3 x 800 m, with a pause of 3-5 minutes. In the third week mainly anaerobic non-lactate load was used: 3 x (4 x 15 m) in maximal speed, with the interval between sets of 2-3 min, and 10 min between series. At the beginning of each consecutive week, the athletes' perfor­ mance capacity during the 45 s test on ergometer and the swimming speed in the 50 m distance were tested. After the anaerobic lactate training on all occasions both the performance capacity and the swim­ ming speed enhanced and surpassed the initial (before the strength training period) level. After a week of aerobic training, the results in both tests did not change significantly, while in the third week, af­ ter sessions in a highly intensive anaerobic non-lactate regime both test results rapidly increased and in most cases reached the person­ al record level. Muscle circumference and strength did not change significantly in the course of three weeks. Conclusions 1. The highest increase in power and performance capacity is achieved through a combined strength training method using submax­ imal weights which facilitate muscular hypertrophy, and using medium weights and performing exercises with maximal power which increases performance capacity through mechanisms of nervous coordination. 2. Strength training may have positive as well as negative effect on swimmers. The positive effect in the enhancement of muscle circumference, power and performance capacity, while the negative effect is a weakening of coordination, technique and the feeling of water. 3. Strength training must be sufficiently long and a effective in order that the muscle circumference, power and performance capacity could increase significantly. Otherwise the negative effect of strength training on swimming speed can be more expressed than the positive one. 28 4. Strength training must be suspended not earlier than 5-8 days before competition. If suspended earlier, the muscle circumference and performance capacity would decrease significantly. 5. After suspending strength training, swimming loads must be in­ creased in an anaerobic, non-lactate regime which, in comparison with other training regimes, produces the greatest increase in performance capacity and swimming speed. REFERENCES 1. Anderson, Т., Kearney, I. T. Effects of three resistance training programs on muscular strength and absolute and relative endurance. — Research Quarterly for Exercise and Sport, 1982,53,1-7. 2. Gillespie, J., Gebhard, С. A test of three theories of strength and muscular endurance development. — J. Human Movement Studies, 1984,10,213- 223. 3. Holloscy, I. O. Metabolic consequence of endurance exercise train­ ing. Eds. E. S. Horton, R. L. Terjung. Exercise, Nutrition and Energy Metabolism. New York, Macmillan Publ. Co, 1988,116-131. 4. Hortobagy, Т., Katch, F., Lachance, E Effects of simultaneous training for strength and endurance on upper and lower body strength and running performance. — J. Sports Med. Phys. Fitness. 1991, 31,20-30. 5. Medbo, J., Tobata, I. Relative importance of aerobic and anaerobic en­ ergy release during short-lasting exhausting bicycle exercise. — J. Appl. Physiol. 1989,67,1881-1886. 6. Saltin, В., Gollnick, P. D. Skeletal muscle adaptability: Significance for metabolism and performance. — Handbook of Physiology. Skeletal Mus­ cle. Baltimore: Williams a Wilkinson, 1983,555-631. 7. Schmidtbleicher, D. Applying the Theory of Strength Development. Pre­ sented at the 1 st. Workshop of the European Athletics Coaches Associa­ tion, "Strength Training Programs". Leuven, Belgium, January 18,1986. 8. Tesch, R, Karlson, J. Muscle metabolite accumulation following maximal exercise. — Eur., J. Appl. Physiol. 1984,52,243-246. 9. Tesch, R, Lindeberg, S. Blood lactate accumulation during arm exercise in world class kayak paddlers and strength trained athlets. — Eur. J. Appl. Physiol. 1984, 52,441-445. 10. Абсалямов Т. M., Ляшко Г. И. Специальная скороотно-силовая подготовка пловцов спринтеров. Плавание, М.: ФИС, 1988, 26. 11. Верхожанский Ю. В. Основы специальной физической подготов­ ки спортсменов. М.: ФиС, 1988, 331 с. 12. Виру А. А., Зимкин Н. В. Развитие нервно-мышечных и эндокринных механизмов мобилизации функциональных резервов организма в процессе тренировки в разных видах физических упражнений. — Тез. докл. V. Всесоюзного симпозиума "Эколого- физиологические проблемы адаптации", М., 1988. 29 13. Зевов Б. Д., Кошкин И. М., Вайцеховский С. М. Специальная физическая подготовка пловцов на суше и в воде. М.: ФиС, 1986, 80 с. 14. Клинский М. Н., Курский М. Д., Осипенко А. А. Биомеханические механизмы адаптации при мышечной деятельно­ сти. Киев: Высш. школа, 1986, 178 с. 15. Коц Я. М. Спортивная физиология. Мл ФиС, 1986, 240 с. 16. Манцевич Д. Е., Петрович Г. И. Научно методические аспек­ ты многолетней силовой подготовки пловцов. Теор. и практ. физ. кули., 1987, 12, 26. 17. Озолиншь П. П. Адаптация сосудистой системы к спортивным на­ грузкам. Рига, "Зинатне" 1984, 134 с. 18. Панин JI. Е. Биомеханические механизмы стресса. Новосибирск: Наука, 1983, 233 с. 19. Платонов В. Н., Вайцеховский С. М. Тренировка пловцов вы­ сокого класса. М.: ФиС, 1985, 256 с. 20. Шакирзъянов М. С. Рефлекторная циклография и перспективы ее применения в спорте. Тр. ЛГИФК, Рига: Звайгзне, 1969, 33. 21. Ээпик В. Э., Виру А. А. Динамика протеиносинтеза при напря­ женных режимах мышечной деятельности. — Тез. докл. V. Всесоюз­ ного симпозиума "Эколого-физиологические проблемы адаптации". М., 1988. 22. Ээпик В. Э., Виру А. А. Специфика адаптивного протеиносинте­ за при выполнении упражнений на выносливость. — Теор. и практ. физ. культ. 1990, 5, 24. 23. Юримяэ Т. А., Олейник И. А., Лепп Т. А. Изменение фи­ зической работоспособности и липидного состава крови в течение комбинированной программы по развитию силы и выносливости у студентов-неспортсменов. Физиология человека 1990, 5, 132-136. 30 ANTHROPOMETRIC DETERMINATION OF NUTRITIONAL STATUS OF PRIMARY SCHOOL CHILDREN IN NIGERIA A.P.Agbonjinmi Department of Physical and Health Education Lagos State University Ojo, Lagos, Nigeria Abstract This study was designed to evaluate the nutritional status of primary school children on class and sex basis. One hundred and twenty-six (126) children attending different primary schools in Ojo Local Government area of Lagos State were randomly selected for this study. The following anthropometric variables were quantified: height in cm; weight in kg; chest and head circumferences in cm. Expected weight for height was computed for all the subjects. The degree of wasting was determined as the actual weight of the children expressed as a percentage of the expected weight for height. The nutritional status of the children was determined ac­ cording to McLaren and Read's standard. Chest-head ratio and Ehrenberg's formular were also applied in the determination of nutritional status. Descriptive statistics were employed in the treat­ ment of data. The study revealed that moderate and severe protein-energy malnutrition (РЕМ) were most prevalent in the junior primary classes and marasmus is most common among female children. Obesity was most prevalent in the upper primary classes, especially in male children. It was concluded that Nigerian children were not adequately fed. Anthropometric indices of weight, height, body circumference, body girth and skinfold are accepted signposts of nutritional status of children [3, 4, 6, 9, 10, 11, 13]. Dugdale and Lovell [2] used anthropometric indices of height and weight for quantifying chil­ dren's obesity and proposed body mass index as a useful tool in the assessment of nutritional status of children; the index is indepen­ dent of age and sex. Expected weight for age has been frequently used in the assessment of nutritional status of children [3, 4]. The use of weight for age in evaluation of nutritional status was report­ ed as concealing two different nutritional conditions: stunting and 31 wasting [13]. The use of weight for age in nutritional surveys is also limited in the third world countries where records of age are hard­ ly or inadequately kept. The expected weight for height which is independent of age, sex and race [3,7] has been suggested for com­ munity nutritional surveys. Ehrenberg's lawlike relationship [5,6, 13] between weight and height which is also independent of age, sex and race, has also been suggested as a measure of nutritional status in children. The primary objective of this study was to evaluate the nutri­ tional status of primary school children on class and sex basis. Methods and Procedure Subjects: One hundred and twenty six (65 females and 61 males) public primary school children in Ojo town, Ojo Local Government area, Lagos, were randomly sampled for this study. These children were regarded as urban non-privilege because they were drawn from free public primary schools. Anthropometric measures: The following anthropometric vari­ ables were quantified: height in cm; weight in kg; chest and head circumferences in cm. Standing height was quantified in cm as described and recom­ mended by Nelson [8] on a stadiometer. The subject stood erect, heels, buttocks, upper part of the back and occiput against the verti­ cal upright of the stadiometer. Arms were freely by the sides. The external auditory meatus and the lower border of the orbit were in a plane parallel to the floor. Nude weight was quantified in kg on a Soehnle spring scale with provision for recalibration. Subjects were asked to stand erect prop­ erly on the scale with body weight evenly distributed between the two heels. Chest circumference was measured in cm in mid-respiration using a new cloth tape. The site of measurement was at the substernal notch in a plane at right angle to the vertebral column. Chest measurement was taken thrice and the mean computed. Computation and Classification Expected weight for height was computed from Weech's [15] equa­ tion using the actual height of individual subjects. The degree of wast­ ing was determined as the actual weight of the child expressed as a percentage of the expected weight for height. McLaren and Read's 32 [7] standard was used in classifying subjects into one of the following classes: (i) Above 110% Obesity (Ü) 90-110% Normal (iii) 85-90% Underweight or mild protein energy malnutrition (РЕМ) (iv) 75-85% Moderate РЕМ (v) Below 75% Severe РЕМ Clinical observations were also earned out. Subjects with actual body weight below 75% of the expected weight for height and without oedema were classified as marasmus while those with oedema were classified as kwashiorkor. Chest-head ratio was also computed for the subjects. A chest-head ratio of less than 1 has been suggested as a positive anthropometric sign of malnutrition in children [10]. Using Ehrenberg's lawlike relationship between height and weight, Kpedekpo [5] and Lovell [6] observed that the degree of deviation of a constant, C, from 0.4 was possibly related to nutritional status. Ehrenberg's lawlike relationship [6] states that: С = 53 (log -0.8 hin where; w is the mean weight in kg; h is the mean height in m. Analysis - Descriptive statistics and percentages were employed in the treatment of data. Results and Discussions Table 1 shows the means for height, weight, chest and head circum­ ferences of the subjects on sex and class bases. The female samples had a mean height of 131.7cm ±12; mean weight of 25.21kg ±7.57, mean chest circumference of 60.85 ±6.02; and a mean head circumference of 52.48cm ±1.96. The male samples had means of 130.64cm ±12.39; 25.25kg ±7.14; 62.33cm ±5.65 and 53.03cm ±1.82 for height, weight, chest circumference and head circumference respectively. Table 2 shows the means for expected weight for height, percent expected weight, chest-head ratio and Ehrenberg's constant, C, on class and sex bases. The female samples had means of 29.3kg ±5.78; 85.45 ±3.9; 1.16 ±0.07 and 0.33 ±0.02 for expected weight for height, percent expected weight, chest-head ratio and С respectively. The male samples had a mean of 28.8kg ±5.71 for expected weight for height and means of 87.42 ± 4.69; 1.18 ±0.07 and 0.34 ±0.02 for percent expected weight, chest-head ratio and С respectively. 5 33 I (N Г-; r- CN О 1П 00 eti ü iH t*H tH т-l i—1 тН гИ H •s «-eлHo v-oH - H - H - H - Hos ^ ^in Hvo - H ЧО 00 vOqn Оч irHt сСоП 43 и iinn mon ö no чо чтог ovos vcoi iinn пrh £о> \q oГo- ^о нTt ci ci V) tri VC К .SP -inн i-nн -н-н-н-н-н C^ CO О in c5 «n c3 )< HC4 Ccn4 ChS <04\ rCfO c1Лi (4N0 •-гч ^d̂5- CO 0T0j- CNOO CONO tj- «n с- с- c- oo d -H -H -n i-nH v-Ho -H 4? i C« Th 00 On Tfr 00 CO >П О CS CO ЧО со i> xd oo «n ö H 61 M fO (O t со X 1т-Н1 ОrH 1О—I огН 1О- ОтН 1-1 ЧО § ON ЧО TJ- ЧО VO ЧО *n О On Tf CJ ON ON rH i—H 1-Ч 1—1 С4и ) 1-Н 1-Н тз -Н-Н-Н4Ш-Н-И л 00 NO NO in 00 00 <о rH СП г-; On Tt р Xh iгnЧ in cini icni cX inj m^ cmi Sо p_ rp~ C00l Оin VсOо NrHO СpЧ ci cj со ЧО xi" «п ЧО m-H r-H- -oHo vo -H -H m-H 4) CO H 00 CO О ̂ 00 5Uе? ЧinО m OmN 0in0 ON Ö no чо no 4 h-hhm l~; ЧО l~: 00 V)I cI i in c-i Ы fi r-' vi oö r-i4n1 -mH -H Ш-H Н-H 1-HП -H О О Tf CO OНj 0H0 1O-n CcO4 OQ 0Qcn es сTоf Icn4 Г> CN 00 CO Pin ЧО 1-5 On ЧО ci § Г- NO in in NO Tf r4 00 NO ЧО N 00 тЧ к К ON ЧО 1-H H N CSCOCO^CO О О Tj- о ̂ О in f-H 1-H 1—t rH 1-Ц 1—I VO H N CO ^ in NO и cs Я -я о о О О ОО О о о О О ОО О $оэ ^ -н -н -Н -Н -н -н -н 00 СП Г^- ON т-Н Г- 00 б р н н N CS 1-j И Н Н т Н r—i тГ ON IH сп Г-» Оч ON ON О *Н |> \0 ON ЧО ON чо г-5 ,-Ц rt -н 0-нS 0 -н 1-Лн 5 -VнO -CнS _ О СП ON ON (S н00 i0n0 i0n0 S00 ОOx ON S00 чOnо сOпn чvоo 00 сСпП гн гl>Ч on t-ч es сп сп xh tn tn £ -н-н-н-н-н-н-н i r чЧоО rчHо IO>N rvHo Tf ЮCS 00 а-« öCS CinS CчSо r-J es" VO oo СП СП СП CS О О О О О rH 1-Н 1-4 ч—< х—I ^-1 т—t ЧО о оCS оTl- оrf о£•• о оCS о о о о о о о • СC -SнП н -н-н-н СП СП СспП С -Пн -.чно -н СП СП ССПП о о о о о о о •cоd Jj О о < I ОГ- OРv оin го- ог-Я «g Р о о о о о о 8 -н-1-н1 -н-н-Nн-н-тЧ rH CS C«S3 r-« н r—i r—i < б 00 Th ON ON vo СП г-н p 00 чо ON К rt ON К СП Tt СП -mн T-нj* -н -O\HpOe нs 5 3h0"0d- -н T mf $ es* Ö VO vo >n T-5 in 00 00 00 00 00 ON 00 00 ЧО 00 *-н on Tt in rf ON t> CS CS* СП чо vi сп in -н-н -OнN -vиo 4i -H -н is 00 CS 8 § СП йй 8* сС4П ССПП SСП COSN o o t o н он юm rH CN СП Tf 1П чо — 5* Presented in Ikble 3 is the nutritional status of subjects, in percent­ ages, based on McLaren and Read's [7] standard. 3.08% of the fe­ male samples were obesed while 4.92% of male samples were obesed. 23.07% of the female samples and 24.5% of the same samples were within the range for well-fed children. 16.92% of the female samples and 22.95% of the male samples suffer from mild РЕМ (underweight). 44.26% of the male samples and 44.62% of the female samples suffer from moderate РЕМ. Oedema was not present in any of the subjects. Therefore, none of the subjects suffer from kwashiorkor. However, 12.31% of the female samples and 3.28% of the male samples suffer from marasmus - severe РЕМ. Of the total sample, only 3 female subjects (4.62%) and 2 male subjects (3.28%) had a chest-head ratio of less than 1. Of the total subjects, only 6 females and 7 males (10.32%) had С value of 0.4 and above. The result of this study revealed that moderate and severe РЕМ were most prevalent in the junior primary classes (primaries 1-4) and marasmus is more common among female than male children (Ta­ bles 2 and 3). This result is supported by the previous findings of Gomez [3], Waterlow [13], Lovell [6], Shakir [10] and Kpedekpo [5]. Obesity was most prevalent in the upper primary classes (primaries 5 and 6) and most common among male children (Table 3). These findings can be attributed to nutritional and weaning practices com­ mon in most Nigerian communities. It is the erroneous belief of most Nigerian illiterate adults that food items such as meat, eggs and milk are required only by the adults. The consumption of meat and meat products by children, the adults belief, coiild inadvertently result in ex­ travagance and stealing. The prevalence of marasmus among females could be due to the preference shown for male children by Nigerian parents. This could probably result in more food attention, especial­ ly protein food items, for the male child. The food attention factor could also account for the high incidence of obesity in male children in upper primary classes. Also, the practice of Weaning children on carbohydrate diets may have contributed to the findings of this study. The improvement in the protein energy status of upper primary school children could be attributed to the provision of mid-day meals in schools. This could also be due to the fact that upper primary school children could, to some extent, be responsible for what they eat outside their family homes. The result of this study further revealed that inadequate food intake, especially protein energy intake, may be the most limiting growth factor in these age groups. Shakir et al. [10] observed that a chest-head ratio of less than 1 was a reliable test for malnutrition in infants. In this study, the mean chest-head ratios of 1.16 ±0.07 and 1.18 ±0.07 were obtained for female and male subjects respectively. These findings contradict the 36 $ £ xf- ^ * 00 r4 00 J О О о *"! о I I I I сл CS CS ON Г- 1—1 c4 сп 15 m $V-) IN VO °f i£2£ о 00 Tl" 4-i оГ- оin in «Л оГ- о VO CN 00 rf о о ui СЛ СП 3 3 R I t s? S* CS tn •A 8 88 28 о £!8 оСП н оtn ON OS 00 cs es 1 v-oH C(SS sо $ ® Ä $s * $ ОС- Oо tn N CS OяN о £8 о о о СП СП Tf- 88 СП RS *о ^ >S ър ^ ̂ II II II II on ̂ §: g; oo es 1 PS SS 32 3 ОrHт -vH» oi—i oiH TтНf io—l Oi—l OтН «r—-<4 От—I O1—4 Or-t NtnO Vr-O4 C8/3 fcS kS feS HS fcS fc-S fcS (N ci и £ £ £ £ £ £ practice sessions of four VJs per session with two minutes rest between the sessions were allowed. Tvo minutes after the second trial session, VJ was evaluated. Three test jumps were allowed and the mean computed as the value for VJ performance. Leg mechanical power (LMP) in ft-ibs was computed from the measures of NBW and VJ performance [2]: LMP (ft-ibs) = VJ (ins) x NBW/12. Analysis Descriptive statistics, the student's t-test of significance and the Pearson product-moment correlation (r) were employed in the treat­ ment of data. The alpha level was set at 0.05 (p < 0.05). Results The mean ± SD and the range for the measured and computed variables are shown in Ihble 1 on sex basis. The correlation co­ efficients (r) between LMP and measures of body weight, height, calf and thigh girths are shown in Ihble 2 for male and female subjects. The study did not reveal any significant differences in age, calf girth, vertical jump performance and LMP among the two sexes. Sig­ nificant differences in favour of the female were revealed in weight, height and thigh girth. The two sexes did not vary much in age, calf girth and VJ per­ formance. The mean age for the boys was 10.89 ± 1.34 years while the average age for the girls was 10.9 ± 1.17. However, the female 42 subjects revealed much variation in nude body weight, height, thigh, girth and LMP compared with the males (Table 1). Table 1 Means, standard deviations and range of anthropometric variables, vertical jump and leg mechanical power on sex basis Male (n = 27) Female (n = 20) Variable Range Range Age, years 10.89± 1.34 8.0 -14.0 10.9 ± 1.17 9.0 -14.0 Wt., Lbs 55.77± 5.4 46.2 -64.9 62.51±12.06 44.66-99.0 Ht., ins 52.7 ± 1.84 49.0 -58.0 54.65± 3.2 51.0 -63.0 Calf c, cm 25.25± 2.6 21.5 -36.5 26.55± 2.76 22.0 -24.3 Thigh c, cm 36.01± 2.25 32.0 -39.0 39.6 ± 3.16 34.0 -49.0 VJ, ins 11.09± 2.16 6.3 -14.96 11.02± 2.23 6.3 -13.78 LMP, ft-ibs 51.99±12.99 25.99-76.76 57.74±16.25 23.45-95.87 Except for calf girth, other anthropometric variates correlate sig­ nificantly with leg mechanical power in male subjects. Nude body weight revealed the highest correlation (:7408) while calf girth corre­ lated poorly (.3308) with leg mechanical power. Table 2 Co-efficients of correlation between leg mechanical power, body weight, calf and thigh girths in primary school children on sex basis r Leg Mechanical Power vs: Male Female Nude body weight .7408* .7121* Thigh girth .6569* .7268* Height .5971* .5081* Sum of Calf and Thigh girths .551* .7635* Calf girth .3308 .5935* * Significant at 0.05 Leg mechanical power in females significantly correlates with all the anthropometric variates that were examined in this study. The highest correlation co-efficient was shown by the sum of calf and thigh girths (.7635), followed by the thigh girth (.7268). Leg mechanical power and height revealed a r of .5081 in females. It is pertinent to emphasize the increase in r when leg mechanical power was correlated to the sum of the calf and thigh girths in female subjects. This, however, was not the case with the males. 6* 43 Discussion The mean height of 52.7ins ± 1.84 for male subjects is similar to that reported by Johnson [8] for Lagos urban adolescent males of comparable age; however, the male subjects of this study were 7.331bs lighter than Johnson's [8] male subjects. The female subjects of this study were also of similar height with Johnson's [8] female subjects of comparable age but were 8.991bs lighter than Johnson's [8] female subjects. The subjects of this study (females and males) were also of comparable heights but lighter than 1964 West Indies primary school children of comparable age [1]. The probable nutritional implication of this finding is that Lagos urban children were better fed in the 1970s than now; and that under-nutrition grossly affects soft muscle and fat tissues rather than skeletal tissue. It can be concluded that the subjects of this study suffered from acute malnutrition. The result of this study in respect of the significantly higher values for height, weight and thigh girth in the females is in conformity with the data of Johnson [8]. The female subjects also revealed a higher but non-significant value for calf girth. Johnson [8] reported that up to the age of 14 years, girls were on the average taller than boys, while girls aged 10-15 years were on the average heavier than boys. However, these trends are reversed at puberty. Harris [6] observed that bone ossification, dental maturity, as well as physiological and neurological maturity are reached sooner in the female. VJ performance was similar in both sexes. The mean values for VJ performance were 11.09ins ± 2.16 and 11.02ins ± 2.23 for male and female subjects respectively; however, the females revealed a hig­ her but non-significant LMP than the males. The pertinent reason for this observation is that body weight was used in the computation of LMP. Although the females were significantly heavier than the ma­ les, the similarity in VJ performance among the two sexes accounted for the non-significant difference in LMP. The height gain in VJ is due to the strength of leg extensor muscles [4, 5]. The similarity in VJ performance between the two sexes suggests comparable strength of leg extensor muscles. Harris [6] reported differential quantities in muscle distribution in the upper body and the trunk among the sexes while muscle quantity in the leg is similar before puberty. Jenson and Fisher (1972) also reported the same rate of strength increases in boys and girls to about the age of 10. Although not examined in this study, the significantly higher value of thigh girth in the females may be accounted for by subcutaneous fat. Nude body weight showed the highest significant correlation (.7408) with LMP while the sum of calf and thigh girths revealed the least significant correlation (.551) in the boys. The relationship between calf girth and LMP in males was not significant. The sum of calf and thigh girths revealed the highest 44 significant correlation (.7635) with LMP in the females while stature showed the least but significant correlation (.5081). Baumgartner and Jackson [2] reported a correlation range of .70 to .90 between body weight and leg power. This is supported by the result of this study. Granted that other biomechanical and psychological factors that affect the expression of muscle strength are constant for the two sexes, the study revealed that the thigh muscles contribute more to LMP than the calf muscles in both sexes. REFERENCES 1. Ashcroft, M. J., Buchanan, I. C., Lovell, H. C. Heights and weights of Pri­ mary school children in St. Christopher-Nevis-Anquilla, West Indies. — Journal of Tropical Medicine and Hygiene, 1965, 68, 277-283. 2. Baumgartner, Т. A., Jackson, A. S. Measurement for Evaluation in Phys­ ical Education. Boston: Houghton Mifflin Company, 1975. 3. Behnke, A. R., Wilmore, J. H. Evaluation and Regulation of Body Build and Composition. New Jersey: Prentice-Hall Incorporation, 1974. 4. Bender, J. A., Kaplan, H. M., Johanson, A. J. Isometric strength needs in athletic skills. — Journal of Health Physical Education and Recreation, 1963,34, 36-37. 5. Coyle, E. E, Costill, D. L., Lesmes, G. R. Leg extension power and muscle fiber composition. — Medicine and Science in Sports, 1979,1,12-15. 6. Harris, D. V. The Female Athlete: Strength, Endurance and Performance. Ed. E. J. Burke. Towards an Understanding of Human Performance. N.Y.: Mouvement Publications, 1977. 7. Ikai, M. Steinhaus, A. Some factors modifying the expression of human strength. — Journal of Applied Physiology, 1961,16,157-163. 8. Johnson, Т. O. The Physique of Urban Nigerians in the Adolescent Period. — Journal of H-opical Pediatrics, 1972,18,134-138. 9. Mathews, D.K . Measurement in Physical Education. 5th edition. Philadel­ phia: W. B. Saunders Company, 1978. 10. Wilmore, J. H., Behnke, A. R, Predictability of Lean Body Weight through Anthropometric Assessment in College men. —Journal of Applied Phys­ iology. 1968, 25,349-355. 45 ON THE THRESHOLD VALUE OF THE PHYSIOLOGICAL LOAD OF PHYSICAL EDUCATION COURSES IN COLLEGES AND UNIVERSITIES Zhao Shunlai, Luo Honglu Department of Physical Education, Shenyang Teachers College, China Major achievements have been made in the study of the physiolog­ ical load in sports by the medical circle all over the world, however the studies on the physiological load in the physical Education Courses in schools are still in their preliminary stage. The theories of values of physiological load have equipped us with methods and theoretical foundations to further carry out the study on Physical Education in schools. In order to improve the scientization of our physical ed­ ucation in schools, esp. colleges and univerisities, further practical studies and discussi ons about the standard and methods of the thresh­ old values of the physiological load in college physical education are needed. Object and Metod of Study Object of Study In reference to the Provincial Authority's evaluation towards the physical education in colleges and universities, a total number of over 300 colleges and universities and more than 600 students were tested regarding the physiological load of physical education classes. Method of Study a) Chinese made Remote Heart Rhythm Sensors Were adopted to record pulse data, the physical load index in the physical education classes. b) Data were recorded when the testees' pulse was at 120-140/min, over 140/min and below 120/min, (named respectively X, S and SX). c) The mathematical model of the physiological load was built up 46 Dv = TV km D = T Km r R Dv: the increasing speed of Heart Rhythm Tv: exercising time Dr: recovering speed of the Heart Rhythm TR: time of recovery of Heart Rhythm Km: intensity of exercise m: coefficient of intensity П. Analysis of the Reselts 1. Standard judging of the threshold valae of the physiological load in the physical edecation classes a) According to the statistics of the surveys, the changes of the physiological load of the tested students are in direct proportion to the exercising time and the coefficient of exercising intensity. Meanwhile, the volume of the physiological load is connected to the levels of the specific content of the education. This proves that in the same repeated physical exercise, there are the differences in the exercising volume, length of the breaks, speed and intensity of every exercise. Therefore, the volume of the physiological load is not merely the kind of relation between the volume and intensity; we should also consider some other elements such as the contents of education and exercises. b) In reality, we found that in 87% of students the physiological load volumes are within the valid range, i.e. pulse volume ranging from 120 to 140 beats per minute. 88% of them were able to keep this state for 2/3 of the whole class periods, and only 8.19% of the tested students went above the valid threshold value, however the differences have no statistical significance. c) During the survey, all of the tested students felt that the in­ tensity of the P. E. classes is physiologically acceptable. But those boy students who were tested in 1000 metre running and girl students who where tested in 800 metre running, all exceeded the physiological load volume standard, and among students who attended the prac­ tising basketball and soccer matches, 63.5% were able to exceed the physiological load of 150/BPM pulse rate, and held on to that state for 1/3 of the whole class time. These figures show that introducing high intensity sporting events to colleges and universities has its special meaning in enhancing the physical condition of the students. d) The statistics proved: the pulse rate between 125 to 156 BPM, which indicates the physiological load of the college students, is a valid threshold value of their physiological load. And the above mentioned rate must be kept for 2/3 of the whole class time. This volume fits the reality of the physical education in our colleges and universities. 47 The measurement of the physiological load volume and the choosing of the evaluation method In the practice of physical education, we need to have a fast as well as an exact method to measure the physiological load volume of the students. Therefore, this thesis also focuses upon the question of choosing the right way of measurement in order to promote the level of scientization of physical education by applying the threshold value of physiological load. a) Reverse computation of the Pulse Rate Recovery after Classes We can calculate the pulse rate of the students during and after classes respectively by applying traditional methods of measuring and processing the pulse rate datas. Therefore, using arithmetical knowl­ edge, we will be able to build up the following formula indicating the relations between average pulse rate during the classes and the recovering pulse rate within 3 to 5 minutes after classes: у = a + bx (y = calculated average pulse rate, "a" and "b" are coefficients, x = recovering pulse rate volume) b) Applying the "Vector Model" testing and data processing method Design a "Vector Model" by using mathematical theories, using the pulse rate datas taken during and after one class, we can obtain the physiological load volume of the class. c) Applying Step Regression and Charts We can build up the following regression model using the average pulse rate volume and the recovering pulse rate volume: у = b0 + B} + Bj (y = calculated average pulse rate, b = coefficient, x = recovering pulse rate volume) Ш. Conclusion 1. According to this Threshold Value theory, also with the reference of the survey results of a certain number of colleges and universities within Liaoning Province, we recommend that the standard volume of the threshold value of the physiological load for our colleges ranges from 125 to 156 BPM, which is also supposed to be kept for 2/3 of the whole class time. Only in this way can we reach the goal of promoting the physical conditions with our physical education method. 2. AS to the theory of threshold value of physiological load, when used in practice, we should always pay attention to all the elements and factors, and also the specific content of our teaching as well as the intensity of the repeated exercises of the same content. In this way, 48 we can correctly apply the theory, which will certainly be a very stable foundation for our sports education practice. 3. The teachers in colleges and universities are strongly recom­ mended to master this theory, esp. the correct method of measure­ ment and evaluation and also all kinds of data processing techniques. This will surely enhance the scientization of our physical education. REFERENCES 1. The Science of Pulse Rate. 2. Ten year of the reform of physical education in primary and middle schools of Liaoning province by Sun Changlin, Liaoning Education Press, 1991. 7 49 STUDY AND ANALYSIS OF ELECTROENCEPHALOGRAMS OF COLLEGE STUDENTS WHO ARE ON DIFFERENT SPORTS TRAINING LEVELS Sui Lu Department of Physical Education Lia Oning University, China The functional state of the Central Nervous System (CNS) is the essential element which affects the forming and developing of human exhaustion. The function of the nervous system decreases when a human being is physically fatigued. We can clearly see from the researches conducted by numerous medical researchers that it is a rather common method to perform studies and observations from the angle of medical nursing and bedside practice, and on the other hand, to study the electrical waves produced by the cerebral cortex during the process of cerebral exhaustion and the relationship between sports training and the relavant characteristics of the Electroencephalogram (EEG) are seldom applied. We are going to discuss how the sports training level can influence the EEGs of college students on the basis of comparative analysis of their EEG charts. I. Samples and Methods of the Study 1. Samples 50 college students who previously had a minimum sports training experience of 3 years, among whom 24 are boys and 26 girls; another 30 ordinary college students who had no sports training experience before, among whom 20 are boys and 10 girls, for comparative study. 2. Methods a) Instrument applied is the Chinese made MD-82B EEG ma­ chine; b) Procedures: sample figures were displayed on the machine before testing, single record was applied, 10/20 System was adopted in the placement of the sensors. Sample students were in a close space, in the sitting position, and the following datas were recorded: 1) EEG datas when testees are quiet; 50 2) EEG datas when testees are under pressure (with 30" prelimi­ nary testing figure), and EEG datas when testees are physically tired; (the first one after); 3) EEG datas when testees are recovering from the state of ex­ haustion (the third one after). Under pressure means that the testees' arms were to be burdened with heavy objects (10 kilograms for boys and 5 for girls), with an 85°- angle between the fore-arms and upper-arms (elbows be kept away from all body parts), for 3 minutes each time, until testees can not hold the position any longer. 3. Data Processing. П. Analysis of the Test Results 1. Comparison when all the testees are quiet There is no significant differences between the Index a, the am­ plitudes of the "a" waves of each group of students tested (T < 1, P > 0.05). Among the indexes and datas of each testing group, 16% of all the testees had shown slight abnormality. 2. Comparisons when all the testees are burdened The changes in the "6" waves and "0" waves are not statistically significant enough to be recorded. The ß indexes of both test groups increased, there were no big changes in the index and amplitudes of the 6 wave. 3. Comparisons when all the testees are fatigued Through comparative analysis on the EEG charts of all tested groups, only the increase of 0 wave is worth recording. 4. Comparisons when recovering from exhaustion The groups that had sports training experiences before recovered faster than other groups. Ш. Conclusions 1. Through the EEG charts, we can see that 16% of all the testees had shown slight abnormalities which indicated that they are on their edges, and the percentage of the group with previous sports training is higher than that of the group with no sports training history. I think that some students who had sports training experience have shown the early symptoms of over-training, but these features did not gain proper attention. 2. The EEG feattire of a human being when he is quiet and calm, has nothing to do with his sports training level, since no significant differences in the indexes and amplitudes of the "6" waves occured 51 MODELING AND MOTOR LEARNING A Mini Review L. Raudsepp Institute of Sports Pedagogy, University of Tartu, 18. Ülikooli Street, Tartu, EE2400 Estonia Introduction Modeling is a general process in which observers attempt to repro­ duce the action demonstrated by another person. Within the realm of sport and physical education, the process of modeling serves its most important function in the demonstration and acquisition of motor skills. However, this critical teaching technique is not well under­ stood owing to the paucity of literature examining the process and product of skill modeling. Perhaps this lack of empirical attention has been due to the complexity of the modeling process. Because motor skill modeling involves both physical and psychological processes, one must integrate information from the literature on motor behavior, social psychology, and biomechanics to understand its effects on skill learning. 1. The functions of modeling Modeling can be defined as the cognitive, affective, and behavioral changes that result from observing others, while models are individ­ uals whose behaviors, verbalization, and nonverbal expressions are attended to by observers [18]. Traditionally, modeling has served three functions in affecting the behaviors of observers [1,2,17]. First, observational learning effects represent the acquisition of new skills and behaviors by the observer. When subjects see repeated demon­ strations that draw attention on the salient aspects of a skill, in combi­ nation with appropriate and contingent feedback, this leads to positive changes in learning and performing skills [25,27]. A second function of modeling concerns the response facilitation. An observed model is used to encourage a behavior that may not otherwise have been emitted [14, 27]. The third function of modeling is described as its inhibition/disinhibition effects on behavior. This function focuses on 53 reducing avoidance behaviors through effects of observer's psycholog­ ical response such as self-confidence, motivation, and anxiety. These psychological effects of modeling have been studied extensively and reported in the clinical, health, and educational psychology literatures [14,18]. The three functions of modeling account for developmental, learning, and social psychological changes in observers, and thus the topic of modeling extends knowledge from the areas of motor learning and control, motor development, and sport psychology. 2. Theoretical perspectives Modeling theories provide a valuable resource because they help to explain how individuals perceive visual demonstration as well as which aspects of a demonstration learners focus on and retain. Knowing the how and what of visual perception enables one to develop practice that promotes optimal demonstrations [4,13]. To date, the majority of investigations exploring modeling have been based on Bandura's [1] social learning theory, which suggests that modeling influences operate primarily through an informative function, whereby observers symbolically code modeled behavior. Ac­ cording to Bandura, people must learn new motor skills either by direct experience or observation. Most human motor behavior falls into the latter category and is learned observationally through modeling. With respect to modeling and motor performance, variables that have been examined testing Bandura's theory included temporal placement of the model [11], optimal number of demonstrations [4], specific model characteristics [9], and informational and motivational elements of the modeling process [9, 14, 15]. Results from these investigations have shown that models can convey pertinent information to the observer that will enhance motor performance. Observational learning, or modeling, is governed by four com­ ponent subprocesses: attention, retention, motor reproduction, and motivation. The first two subcomponents comprise the response ac­ quisition phase. This phase involves both the process by which individ­ uals discern the important cues from modeled acts and the manner in which the modeled responses are covertly coded and rehearsed. The motor reproduction and motivation are incorporated into the perfor­ mance reproduction phase, during which learners use these covertly coded responses to guide overt behavior. The most desirable outcome of these processes would be attending to task relevant cues that are retained in long-term memory and used to guide responses whereby the individual is both physically capable and motivated [3,13]. These four processes have been corporated in the two-factor theory of imita­ 54 tion developed by Yando et. ai. [29]. He emphasized that the emitted response to modeled events will be determined by two factors: the observer's cognitive development level and his or her motivational system. In 1986, Bandura [2] expanded his understanding of the perfor­ mance reproduction phase whithin his newly titled social-cognitive theory. He suggested that the behavioral reproduction of the indi­ vidual involves a comparison of incoming sensory feedback from the overt enactment to the cognitive conception acquired via the model. Many authors have attempted to provide empirical support for various aspects of Bandura's theoretical approach to modeling [5, 9, 13,14,15]. Scully and Newell [19] proposed an interesting alternative to Ban­ dura's social-cognitive oriented theory of modeling. The salient infor­ mation picked up from modeling, according to these authors, is the observation of the relative kinematic pattern over time. It is thought that if learners can approximate the relative kinematic patterns ob­ served in the demonstration within certain ranges of performance, it might be considered that the skill has been modeled. To examine these relative kinematic patterns it is essential to employ biomechan- ical techniques that allow for quantitative evaluation of kinematic parameters. Southard and Higgins [20] conducted one of the few studies involving a kinematic analysis of the movement sequence dur­ ing observational learning. It was found that a demonstration group was no better than a control group at succesfully changing limb con­ figuration or segments velocities. Cristina [3] strongly advocated an interdisciplinary strategy incorporating both ideas and methods from biomechanics and other fields related to cognitive science in studying issues in motor learning, and in observational learning in particular. 3. Developmental aspects of modeling Observational learning or modeling is a powerful and sometimes unintentional tool for children's motor skill and social psychological development [27,28]. The power of modeling can be seen in children's exposure to new motor skills, attempts at improving previously learned skills. Perceiving a visual demonstration will be a different process at each stage of development, and therefore the developmental idiosyn­ crasies of children need to be considered [21, 23]. Both attention and retention capabilities are significantly different between children and adults. Age related differences in information processing have been supported by empirical studies [8, 22]. In an extensive review 55 of information processing differences between children and adults, Thomas [22] emphasized the need for the use of prompted rehearsal for facilitating children's skill learning. Modeling techniques can be especially facilitative because of the difficulty children have in formu­ lating a visual image based upon verbal description only. Observation of a model allows the child to visually associate the verbal description of a motor task and gain information regarding task relevant cues for successful skill execution [12,28]. Children are slower at processing information and thus require more time to comprehend visual stimuli. In addition, they are unable to selectively attend to movement characteristics until about 12 years of age [8]. Furthermore, younger children have a limited memory capacity and less sophysticated retention strategies [8,22]. While old­ er children and adults spontaneously invoke strategies such as verbal rehearsal and labeling to help,remember, younger children will only adopt such strategies when promted [27]. Several recent developmental studies have examined the role of verbal rehearsal strategies, particulary as an aid to the retention of important modeled information by children. Weiss [24] examined the effects of age, modeling, and verbal self-instruction on the per­ formance of children. Ал observed age by model type interaction indicated that older children performed equally well with either a silent or verbal model, whereas younger children performed best with a verbal model. After extending this investigation, Weiss and Klint [26] concluded that verbal rehearsal strategies aid children's ability to attend selectively to relevant task component and to remember a specific execution order of skills. Similar findings were reported in a study by McCullagh, Stiehl and Weiss [16], which addressed the role of visual and verbal models as well as verbal rehearsal in the skill acquisition process of children. Summary In summary, contemporary modeling theories emphasized the crit­ ical role of cognitive-developmental and perceptual capabilities in the effective reproduction of modeled skills. Attentional capabilities, memory capability, and use of rehearsed strategies must be accounted for in demonstration. Because motor skill modeling involves both physical and psychological processes, one must integrate information from the motor behaviour, social psychology, and biomechanics to understand its effects on motor skill learning. 56 REFERENCES 1. Bandura, A.S ocial Learning Theory. Englewood Cliffs, NJ; Prentice Hall, 1977. 2. Bandura, A. Social Foundations of Thought and Action. Englewood Cliffs, NJ: Prentice Hall, 1986. 3. Cristina, R. W. Motor learning: future battlefronts of research. — The cutting age in physical education and exercise science research. Ed. by H, Eckert. American Academy of Physical Education Papers, No 20, Champaign, IL: Human Kinetics, 1987,26-41. 4. Feltz, D. L. The effects of age and number of demonstrations on modeling of form and performance. — Res. Quar. Exer. Sport., 1982, 53,291-296. 5. Feltz, D. L., Landers, D. M. Informational-motivational components of model's demonstration. — Res. Quar., 1977,48,525-533. 6. Gallagher, J. T. The effects developmental memory differences on learn­ ing motor skills. — Journ. Phys. Educ. Reer. Dance, 1982,53,36-37. 7. Gallagher, J. D., Thomas, J. R. Rehearsal strategy effects on developmen­ tal differences for recall of a movement series. — Res. Quar. Exer. Sport, 1984,55,123-128. 8. Gallagher, J. D., Hoffman, S. Memory development and children's sport skill acquisition. — Advances in Pediatric Sport Sciences. Vol. 1.: Behav­ ioral Issues. Eds. D. Gould, M. R. Weiss. Champaign, IL: Human Kinetics, 1987,187-209. 9. Gould, D., Weiss, M. The effects on model similarity and model talk on self-efficacy and muscular endurance. — J. Sport Psych., 1981,3,17-29. 10. Keele, S. W. Current status of the motor program concept. — Psych. Mot. Behav. Sport. Eds. R. W. Cristina, D. M. Landers. Champaign,I L: Human Kinetics Publishers, 1977. 11. Landers, D. M. Observational learning of a motor skill: Temporal spacing of demonstrations and audience presence. — J. Mot. Behav., 1975, 7, 281-287. 12. Lirgg, C. D., Feltz, D. L. Teacher versus peer models revisited: Effects on motor performance and self-efficacy. — Res. Quar. Exer. Sport,1 990,61, 334-350. 13. Martens, R., Burwitz, L., Zuckermann, J. Modeling effects on motor performance. — Res. Quar., 1976,57,277-291. 14. McGullagh, E A model status as a determinant of attention in observa­ tional learning and performance. — J. Sport Psych., 1986, 8,319-331. 15. McGullagh, R Model similarity effects on motor performance.— J. Sport Psych., 1987,9,249-260. 16. McGullagh, R, Stiehl, J., Weiss, M. R. Developmental modeling effects on the quantitative and qualitative aspects of motor performance. — Res. Quar. Exer, Sport, 1990, 61,344-350. 17. McGullagh, R, Weiss, M. R., Ross, D. Modeling considerations in motor skill acquisition and performance: An integrated approach. — Exercise and Sport Sciences Reviews. Ed. К Pandolf. Baltimore: Williams and Wilkins, 1989,17,475-513. 18. Schunk, D. H. Social cognitive theory and self-regulated learning. — Self- regulated learning and academic achievement. Eds. B. J. Zimmerman and D. H. Schunk. New York: Springer-Verlag, 1989,83. 8 57 19. Scully, D. M., Newell, К. M. Observation learning and the acquisition of motor skills: Toward a visual perception perspective. — J. Hum. Mov. Stud., 1985,11,165-186. 20. Southard, D., Higgins, T. Changing movement patterns: Effects of demon­ stration and practice. — Res. Quar. Exer. Sport, 1987,58,77-80. 21. Thomas, J. R., Pierce, C., Ridsdale, S. Age differences in children's ability to model motor behavior. — Res. Quar., 1977,48,592-597. 22. Thomas, J. R. Acquisition of motor skills: Information processing differ­ ences between children and adults. — Res. Quar., 1980,51,158-173. 23. Thomas, J. R., Thomas, К. Т., Gallagher, J. D. Children's processing of information in physical activity and sport. — Motor development. Ed. A M. Morris. 1981. 24. Weiss, M. R. Modeling and motor performance: A developmental per­ spective. — Res. Quar. Exer. Sport, 1983,54,190-197. 25. Weiss, M. R., Ebbeck, V., Rose, D. J. "Show and tell" in the gymnasium revisited: Developmental differences in modeling and verbal rehearsal effects on motor skill learning and performance. — Res. Quar. Exer. Sport, 1992,63,292-301. 26. Weiss, M. R., Klint, К, A. "Show and tell" in the gymnasium: An investi­ gation of developmental differences in modeling and verbal rehearsal of motor skills. — Res. Quar. Exer. Sport, 1987,58,234-241. 27. Weiss, M. R., Ebbeck, V., Wiese-Bjorastal, D. M. Developmental and psy­ chological factors related to children's observational learning of physical skills. — Ped. Exer. Sei., 1993,5,301-317. 28. Wiese-Bjornstal, D. M., Weiss, M. Modeling effects on children's form kinematics, performance outcome, and cognitive recognition of a sport skill: an integrated perspective.—Res.Q uar. Exer. Sport, 1992,63,67-75. 29. Yando, R., Seitz, V., Ziegler, E. Imitation: A developmental perspective. Hillsdale, NJ: Erlbaum, 1978. 58 EFFECT OF AEROBIC EXERCISES ON BODY COMPOSITION, BLOOD LIPOPROTEINS AND WORKING CAPACITY IN RELATION TO THE INSULIN LEVEL IN BLOOD M. Rehand Institute of Sports Pedagogy, University of Tartu, 18. Ülikooli Street, Thrtu, EE2400 Estonia Abstract The purpose of this experiment was to study the effect of sys­ tematic exercise training on physical working capacity, body weight and composition and blood lipoprotein content depending on dif­ ferent initial levels of insulin. During 8 weeks 121 female university students, aged 18-27, practiced aerobic exercises (aerobic dance or jogging) for three times a week, one session lasting for 50 minutes (HR 140- 150 beats/min-1. "Joggers" (n = 46) and "dancers" (n = 75) were divided into groups according to the initial level of insulin: < 10.0 /iU/ml; 10.0-20.0 ynU/ml; > 20.0 /Ш/ml. Higher level of insulin was in accordance with bigger body weight. Significant correlations were found between insulin levels before and after training, on the one hand, and body weight, fat % and body fat mass, on the other hand. The reduction of body weight as a result of the training was not found in the subgroup of "joggers" with the initial insulin over 10 /tU/ml-1 and in the subgroup of "dancers" with insulin over 20 /xU/ml-1. The training-induced reduction in blood insulin level was most pronounced in persons with higher initial insulin levels. Thus ex­ ercise training normalizes the level of insulin. High level of insulin (>20 \iU/ml-1) abolished the effect of aerobic dance on the im­ provement of PWCito and on the levels of lipoproteins. Both in "joggers" and "dancers" it was found that the higher the initial insulin concentration, the lower was the PWC170 per kg of body weight before and after training. Key words: exercise training, body weight, body fat, plasma in­ sulin, blood lipoprotein, working capacity. 8* 59 Introduction The increase in energy expenditure associated with aerobic exer­ cise training can produce the mobilization of the energy stored in the adipose tissue, if such an increase is not compensated by enhanced energy intake or by decrease in other components of energy expen­ diture. Accordingly, when the energy intake of the subjects was not controlled, aerobic exercise training did not give unanimous results in regard to reducing the body fat [1-4]. However, even in cases of con­ trolled diet the training efficiency is variable. Probably there exist a number of conditions modulating the training effect on body mass and the amount of fat tissue. From these conditions attention must be paid to the individual differences in hormone levels. Many studies have demonstrated that obesity as well as the regional distribution of adi­ pose tissue are related to insulin secretion [5-9]. Obesity is associated with insulin hypersecretion, whereas upper body fat accumulation is related to reduced hepatic insulin extraction and diminished insulin clearance [10,11]. The given experiment was conducted in order to study the effect of systematic exercise training on body weight, working capacity and blood lipoprotein in dependence on different initial levels of insulin. Material and methods Subjects. 136 female university students were subjected to full medical examination by a physician. The students with cardiovas­ cular disease, diabetes or other endocrine disorders were excluded. The students did not have plasma glucose values > 140 mg• 100 ml"1. The oral glucose tolerance test indicated normal glucose tolerance according to the classification of the National Diabetes Data Group [12]. The subjects were divided into the control group (15 students) and two training groups. Exercise training consisted in one group in jogging (n = 46) and in the other group in aerobic dancing (n = 75). The body mass and composition of the subjects are presented in Ta­ ble 1. The age of the subjects varied between 18-27 years. The mean age in the control group was 20.7 ± 0.5 (mean ± S.D.), in the joggers' group 18.6 ± 0.1 and in the dancers' group 20.3 ± 0.2 years. The height of the subjects was 165 ± 2, 167 ± 1 and 165 ± 1 cm respec­ tively. For the analysis of training effects both training groups were further divided by the initial insulin level into subgroups: blood insulin < 10 /AJ/ml-1; 10-20 /Ш/тГ1; > 20 /xU/тГ1. Training. Training sessions consisted of aerobic exercises (aer­ obic dancing or jogging) for 50 minutes at the heart rate of 140- 60 Table 1 Effects of an 8-week exercise training program on body mass and body composition "Dancers" "Joggers" Control group n = 75 n = 46 n= 15 Body weight (kg) before 73.90 ± 1.21 68.50 ± 1.04 74.00 ± 2.29 after 72.40 ± 1.19 66.90 ± 1.08 72.50 ± 2.20 change -1.50 ± 1.70 -1.59 ± 1.50 -1.57 ± 3.17 Body fat (%) before 31.62 ± 0.51 29.77 ± 0.54 32.59 ± 0.97 after 29.04 ± 0.47 27.14 ± 0.58 30.60 ± 1.09 change -2.58 ± 0.69* -2.64 ± 0.79* -1.99 ± 1.46 Body fat (kg) before 23.77 ± 0.75 20.55 ± 0.62 24.42 ± 1.53 after 21.40 ± 0.69 18.25 ± 0.64 22.46 ± 1.51 change -2.37 ± 0.99* -2.20 ± 0.89* -1.96 ± 2.15 Lean body mass before 50.15 ± 0.55 47.93 ± 0.58 49.61 ± 0.85 (kg) after 51.01 ± 0.56 48.54 ± 0.59 50.00 ± 0.89 change 0.86 ± 0.78 0.61 ± 0.83 0.39 ± 1.22 Values are means ± S.E.M. Asterisks denote statistically significant change (p < 0.05). 150 beats/min-1. Exercises were performed three times a week for 8 weeks. During the jogging session the total distance covered was 6.5 to 7.5 km. The sessions of aerobic dancing were organized by the program proposed by Matov et al. [13]. The energy expenditure dur­ ing both sessions was computed by tables [14] and was approximately 400 kcal. The subjects kept a diary where they recorded the consumed food for the calculation of energy intake. The subjects also recorded other muscular activities in addition to the training sessions. The ra­ tio between the total energy expenditure and energy intake was close to 1.0 in the control group (1.02 ± 0.03) and in the dancers' group (0.98 ± 0.01). In the joggers' group the ratio was a little bit lower (0.94 ± 0.01). In dancers who were divided by the insulin level into three groups, the ratio remained the same (0.97 ± 0.02; 0.98 ± 0.01 and 0.98 ± 0.01 to the respective insulin levels of < 10.0 /AJ/ml-1,10- 20 /tU/ml™1 and > 20.0 yuU/ml-1). In the "joggers" with the insulin level < 10.0 /y.U/ml-' the ratio was 0.92 ± 0.01, while in the "joggers" with the insulin level of 10-20 ^tU/ml-1 the ratio was 0.98 ± 0.01. Measurement of total body fat and physical working capacity. Body fat percent was computed by Parizkova [15], Physical work­ ing capacity was assessed by the test PWQ70. The test was performed on a bicycle ergometer according to Karpman [16]. Blood analysis. Venous blood samples were taken before and after the training period (8 weeks) in the morning between 8 and 61 9 a.m. following 12 hours of fasting. The blood sampling was ad­ justed to days 8-14 of the ovarial-menstrual cycle. Insulin levels were determined radioimmunologically [17]. The total cholesterol concen­ tration was determined by the Lieberman-Burchard reaction, high density lipoprotein-cholesterol (HDL-C) by heparin-MnCb precipi­ tation procedure [18]. Low density lipoprotein-cholesterol (LDL-C) was calculated by the Friedewald equation [19]. Triglycerides (TG) were measured using Lachema kits (CSFR). Statistical analyses. Pre-exercise and post-exercise values were compared using the t-test for paired observations. Correlation analy­ ses were performed using the Pearson interclass coefficient [20]. Results Effect of training on the body mass and composition. The studied 8 weeks period resulted in a reduction of body weight in 90% of "joggers", 77.5% of "dancers" and 73% of control persons (Fig. 1). The correlation analysis showed before the training period that the body weight, fat % and body fat mass were significantly related to the initial level of insulin in blood (Table 2). After the training period, the body weight, fat % and body fat mass correlated significantly to insulin levels both before and after the training period. Changes in fat % and body fat mass were in negative correlation with the changes in insulin concentration. Under the influence of training the body fat mass and fat % were reduced significantly only in the subgroups of initial insulin level < 10 /tU/ml-1. In addition to this, the fat % decreased in "dancers" subgroup of initial insulin level 10-20 /zU/ml"1 (Fig. 2). Effect of training on the insulin level in the blood. There were significant correlations between insulin levels before and after the training period in both groups. Thus, the training did not change the interindividual relations in insulin levels. The change in insulin level was more pronounced in persons with higher initial levels (Table 2). Accordingly, training did not cause a significant decrease in the blood insulin level if the initial values were < 10 /iU/mi-1. If the initial level of insulin was higher, a significant decrease was found both in "joggers" and "dancers" (Fig. 3). Effect of training on the working capacity. Training induced signif­ icant increases in PWC170 values in all subgroups except the "dancers" with the initial level of insulin > 20 ^U/ml-1 (Fig. 4). The same re­ sult was obtained in PWCno values per 1 kg of body weight. The lack of improvement in physical working capacity in "dancers" with a high initial insulin level was due to the existence of a person who responded to the training by an increase in insulin concentration and by a decrease in physical working capacity. 62 Joggers Dancers 17% Control group 73% 13% Fig. 1. Frequency of various changes of body weight in various groups. White sector — % of persons exhibiting a decrease of body weight, striated sector — % of persons exhibiting an increase of body weight, black sector — % of persons with stable body weight. By the results of the correlation analysis, mutual relations between insulin levels and working capacity were established when insulin lev­ els were plotted against PWC170 per kg of body weight. The higher the blood insulin concentration before training, the lower was the PWC170 per kg of body weight both before and after training. A negative correlation was found between changes in insulin and physi­ cal working capacity in "dancers". In "joggers" the change in insulin concentration correlated significantly with the change in PWC170 per kg of body weight (Ihble 2). Effect of training on the lipoprotein content in the blood. A gen­ eral result of training was the reduction in the total cholesterol and LDL-cholesterol concentrations. The exception was the subgroup of "dancers" with the initial insulin level >20 /xU/ml-1. In this sub­ group no change in the blood lipoprotein content was found (Fig. 5). HDL-cholesterol level rose significantly only in "dancers" with the initial level of insulin < 10 /JJ/ml-1. HDL/total cholesterol increased 63 T a b l e 2 Statistically significant correlations of insulin levels with recorded indices of body composition and physical working capacity "Joggers" (n = 46) "Dancers" (n = 75) Insulin Insulin Insulin Insulin Insulin Insulin before after change before after change Body weight before 0.63 0.39 0.33 0.39 0.51 N.S. after 0.61 0.36 0.34 0.41 0.52 N.S. change N.S. N.S. N.S. N.S. N.S. N.S. Body fat % before 0.52 0.49 N.S. 0.33 0.52 -0.26 after 0.60 0.31 0.37 0.47 0.53 N.S. change N.S. 0.32 -0.46 N.S. N.S. -0.23 Mass of body before 0.65 0.49 0.28 0.36 0.53 N.S. fat after 0.67 0.36 0.40 0.45 0.54 N.S. change N.S. 0.36 -0.40 N.S. N.S. -0.25 PWC170 before -0.39 N.S. -0.51 N.S. 0.30 -0.27 after N.S. N.S. N.S. N.S. N.S. N.S. change -0.31 N.S. -0.39 N.S. 0.35 -0.35 PWCno per before -0.36 -0.49 -0.33 -0.23 N.S. N.S. kg b.w. after -0.30 N.S. N.S. -0.24 -0.27 N.S. change -0.41 -0.30 N.S. N.S. 0.38 -0.31 Insulin before - 0.45 0.07 - 0.31 0.48 after 0.45 - -0.36 0.31 - -0.68 change 0.67 -0.36 - 0.48 -0.08 - only in "dancers" if the initial level of insulin was > 20 /zU/ml-1. The blood triglyceride content declined significantly in "joggers" with the initial insulin level 10-20 ynU/ml-1 and in dancers with insulin level < 10 /xU/ml-1. No significant correlation was found between insulin and lipoprotein levels. Control group. During the studied 8-week period no significant changes were recorded in body fat %, blood insulin level, or the blood lipoprotein content (levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, HDL/total cholesterol). A significant decrease was found in the blood triglyceride content (-0.27 ± 0.10 mmol/L-1). Discussion In agreement with the significance in insulin hyperproduction in obesity development [10,11, 21] the obtained results indicated at an overall correlation between body weight and basal insulin level in the blood. Before the training period the insulin concentration in the 64 Joggers Dancers 40.00 т 30.00- 35.00 -- зо.оо- 25.00 - 20.00 - 20.00 -- 15.00 -- 10.00 - 5.00 - <10.0 10.0-20.0 <10.0 10.0-20.0 >20.0 INSULIN ци/ml INSULIN ци/ml Joggers Dancers 25.00 т 35.00 т 30.00 20.00 25.00 - 15.00 -- •ё1 с 10.00 f 10.00 - 5 . 0 0 - 5.00 - - <10.0 10.0-20.0 <10.0 10.0-20.0 >20.0 INSULIN ци/ml INSULIN ци/ml Fig. 2. Alterations of body fat % (upper part) and body fat mass (lower part) in two experimental groups in dependence of the initial insulin level in blood. Striated columns indicate mean values before and white columns after the experimental period. The dotted part of columns represents SEM. The asterisks indicate the statistically significant differences between values before and after the experimental period: * p < 0.05, **p< 0.01. blood correlated also with the physical working capacity of persons, estimated by PWCno- Previously the blood insulin level was found to be in correlation with maximal oxygen uptake as well as with body weight [22]. The obtained results confirmed the aerobic training effect on the basal insulin level [23-26]. This training effect was found in result of endurance running as well as of aerobic dancing. However, 9 65 16.00" 25.00т 14.00 - - i 12.00- „ 20.00-- 1 10.00- i 15.00 8.00 -• z 3 6.00 -- 10.00- 3 4.00- - z 2 5.00 2.00-- 0.00 - 0.00 <10.0 10.0-20.0 <10.0 10.0-20.0 <20.0 INSULIN ци/ml INSULIN ци/ml Fig. 3. Alterations in blood insulin concentration in two experimental groups in dependence of the initial insulin level in the blood. For further explanation see Fig. 2. SEM is indicated by cross-striated part of column. Joggers Dancers 1200 T 1200 т- ** 1000-- I 1000 800-- 800- - 6 0 0 - - 600-- 400-- 2 0 0 - - I 200- <10.0 10.0-20.0 <10.0 10.0-20.0 >20.0 INSULIN ци/ml INSULIN ци/ml Fig. 4. Alterations in PWC170 in two experimental groups in dependence of the initial insulin level in the blood. For further explanation see Fig. 2. SEM is indicated by cross-striated part of columns. the training effect was more pronounced in persons with higher initial level. The change was not common in persons with the initial level <10 /tU/ml-1. Therefore the results suggest that the endurance training effect on the blood insulin level is, first of all, a normalizing one. The aerobic training effect on physical working capacity occurred to be in relation with the initial insulin concentration in the blood. This 66 Joggers Dancers I 200т 200 Bs a и 100 U 100 J) Q <10.0 10.0-20.0 <10.0 10.0-20.0 >20.0 INSULIN ци/ml INSULIN ци/ml 500T 500 Q 400 • I 400 В a 300 U 200+ U 200 Л 3 100 S 100 <10.0 10.0-20.0 <10.0 10.0-20.0 >20.0 INSULIN ци/ml INSULIN ци/ml •« I 500 S 600 I 400 J 300 5 200 5 100 <10.0 10.0-20.0 <10.010.0-20.0 >20.0 INSULIN ци/ml INSULIN (iU/mI Fig. 5. Alterations in blood lipoprotein contents in two experimental groups in dependence on the initial insulin level in the blood. For further explanation see Fig. 2. SEM is indicated by cross-striated part of columns. was indicated by two results. (1) In a subgroup of persons possessing an initial insulin level over 20 /AJ/ml-1, the training effect was not found. (2) The higher the blood insulin concentration in blood before the training, the lower was the PWC170 per kg b.w. not only before but also after training. These results suggest that in persons with elevat­ ed insulin level training has to reduce the insulin concentration in the blood to obtain training effect on the physical training capacity. Nega- 9* 67 tive correlations were found between changes in insulin concentration and PWC170. Concequently less pronounced decrease in insulin con­ centration associated with smaller improvements in physical working capacity. Less striking were the relations between insulin levels and training effect on body weight and fat mass. Nevertheless, significant correla­ tions were found between insulin levels before and after training, on the one hand, and body weight, fat per cent, and body fat mass after training, on the other hand. A distribution of persons to subgroups by the initial insulin level indicated that training did not induce reduc­ tions in fat mass and fat percentage in "joggers" with the initial insulin concentration over 10 /tU/ml-1 and in "dancers" with the initial con­ centration over 20 /iU/ml-1. A common effect of aerobic training is the so called antisclerot- ic change in the blood lipoprotein content [27-30]. The obtained results confirm the earlier data [31] that both forms of aerobic train­ ing — running and aerobic dancing — induce corresponding changes. However no significant changes in blood lipoprotein contents were found in "dancers" with the initial level over 20 /xU/ml-1. Thus the high insulin level may aggravate also the training effect on lipoprotein contents. REFERENCES 1. Björntorp, R Exercise in the treatment of obesity.—Clin. Endocr. Metab., 1976,5,431-453. 2. Despres, J.-R, TYemblay, A., Bouchard, C.S ex differences in the regulation of body fat mass with exercise-training. — J. Obesity and Weight Regul., 1989, 45,297-304. 3. Despres, J.-R, Ttemblay, A., Mooijani, S., Lupinen, P. I., Theriault, G., Nadeau, A., Bouchard, C. Long-term exercise training with constant en­ ergy intake. 3: Effects on plasma lipoprotein level.—Int. J. Obesity, 1990, 14, 85-94. 4. Tremblay, A., Despres, J.-R, Bouchard, C. The effects of exercise-training on energy balance and adipose tissue morphology and metabolism. — Sports Med., 1985, 2,223-233. 5. Kissebach, A. H., Vydelingum, N., Murray, R., Evans, D. J., Hartz, A. J., Kalkhoff, R. K., Adams, R W. Relationship of body fat distribution to metabolic complications of obesity. — J. Clin. Endocr., 1982, 54, 154- 160,254-260. 6. Krotkiewski, M., Björntorp, P., Sjöström, L., Smith, H. Impact of obesity on metabolism in men and women: importance of regional adipose tissue distribution. — J. Clin. Invest., 1983, 72,1150-1162. 7. Evans, D. J., Hoffinan, R. G., Kalkhoff, R., Kissebach, A. H. Relationship of body fat topography to insulin sensitivity and metabolic profiles in premenopausal women. — Metabolism, 1984,12,351-357. 68 8. Molina, J. M., Ciaraldi, Т. Е, Brady, D., Olefski, J. M. Decreased activa­ tion rate of insulin-stimulated glucose transport in adipocytes from obese subjects. — Diabetes, 1988,38,991-995. 9. Müller, E H. Hyperinsulinämie bei adipositas typ-II-diabetes und hyper­ tonic. — Aktuel. Endocrin. und Stoffwechsel., 1989,10,33-40. 10. PBiris, A. N., Mueller, R. A., Smith, G. A., Strove, M. F., Kissebach, A. H. Splanchnic insulin metabolism in obesity: influence of body fat distribution.—J. Clin. Invest, 1986,78,1648-1657. 11. PBiris, A. N., Strove, M. E, Kissebach, A. H. Relationship of body fat distribution to the metabolic clearance of insulin in premenopausal wom­ en. — Int. J. Obesity, 1987,11,581-589. 12. National Diabetes Data Group: Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. — Diabetes, 1979, 28,1039-1057. 13. Matov, V. V., Lantsberg, A. A., Ivanova, О. A. Rhythmic gymnastics. — Teoria i prakt. fiz. kult., 1985,1,29-30 (in Russian). 14. Rogozkin, V.A., Pshendin, A. I., Shishkina, N. N. Nutrition of Sportsmen. Moscow: FiS, 1989 (in Russian). 15. Parizkova, J. Body fat and physical fitness. Hague: M. Nijhoff В. V Med­ ical Division, 1977. 16. Karpman, V. L., Belotserkovsky, Z. В., Gudkov, I. A. Research of physical working capacity in sportsmen. Moscow: FiS, 1974 (in Russian). 17. Jaffe, В. M., Behrman, H. R, Methods of hormone radioimmunoassay. New York: Acad. Press, 1979. 18. Burstein, M., Scholnick, H. R., Morfin, R. Rapid method for the isolation of lipoproteins from human serum by precipitation with polya nions. — J. Lipid Res., 1970,11,583-595. 19. Friedewald, W. Т., Levy, R. J., Fredrickson, D. S. Estimation of the con­ centration of low-density lipoprotein-cholesterol in plasma, without the use of the preparative ultracentrifuge. — Clin. Chim. Acta, 1972,18,499. 20. Winder, B. J. Statistical principles in experimental design. New York: McCraw-Hill, 1971,907. 21. Tepperman, J., Tepperman, H. M. Metabolic and endocrine physiology. 5th edition. Chicago, London: Year Book Medical Publ., 1987. 22. LeBlanc, J., Nadeau, A., Boulay, M., Rousseau-Migneron, S. Effects of physical training and adiposity on glucose metabolism and 125I-insulin binding. — J. Appl. Physiol., 1979,46,235-239. 23. Björntorp, P. K., de Jounge, K. S., Sjöstrand, L., Sullivan, L. The effect of physical training on insulin production in obesity. — Metabolism, 1970, 19, 631-638. 24. Lohmann, D., Liebold, F., Heilman, W., Senger, H., Pähl, A. Diminished insulin response in highly trained athletes. — Metabolism, 1978,27,521— 524. 25. Koivisto, V. A., Soman, V., Conrad, P., Hendler, R., Nadel, E., Felig, P. Insulin binding to monocytes in trained athletes. — J. Clin. Invest., 1979, 64,1011-1015. 26. Björntorp, E K. The effect of exercise on plasma insulin. — Int. J. Sports Med., 1981,2,125-129. 27. Dufanx, В., Assmann, G., Hollmann, W. Plasma lipoprotein and physical activity: A review. — Int. J. Sports Med., 1982,3,123-136. 69 28. Schnabel, A., Kindermann, W. Effect of maximal oxygen uptake and dif­ ferent forms of physical training on serum lipoproteins. — Eur. J. Appl. Physiol., 1982,48,263-277. 29. H-an, Z. V, Weltman, A., Glass, G. V., Mood, D. P. The effects of exercise on blood lipids and lipoproteins: A metaanalysis of studies. — Med. Sei. Sports Exerc., 1983,15,393-402. 30. Wood, E D., Haskell, W. L., Blair, S. D. et al. Increased exercise levels and plasma lipoprotein concentration. A one-year randomized controlled study in sedentary middle-aged men. — Metabolism, 1983,32,31-39. 31. Jnrimäe, Т., Neissaar, I., Viru, A. The effect of similar aerobic gymnastics and running program on physical working capacity and blood lipids in female university students. — Hungarian Rev. Sports Med., 1985, 26, 251-256. 70 THE KINEMATICS OF RUNNING AND OVERHAND THROWING IN 8-YEAR-OLD CHILDREN L. Raudsepp, M. Pääsuke* Institute of Sports Pedagogy, "Institute of Exercise Biology, University of Tartu, 18. Ülikooli Street, Tartu, EE2400 Estonia Introduction In studying the movement of a human, it is appropriate to observe and analyze the changing shape of the body and the force used to propel the body. In kinematics, the concentration is on the geometry of motion through distance and time measures of the changing shape of the body, without reference to the forces producing it. Kinematic studies have produced information about displacement and velocity of the body during movement [2,5]. Developmental aspects and gender differences of fundamental movement patterns are usually examined on the basis of movement kinematics [1,2, 6, 8,11,12]. The developmental patterns of running and overhand throwing have certain differences. The kinematics of running resembles the adult running pattern already by the age of 5... 6 years [3, 4]. Results have revealed that gender differences in running kinematics were associated with the movement of the swing leg [5]. Only few studies [2,5,8] have reported developmental aspects of the running pattern in young children. Gender differences in the kinematics of overhand throwing ap­ peared already in early preschool vears and these differences increased with the age [6,9,11]. These differences have been reported to be both qualitative and quantitative in nature. Halverson et al. [6] reported that boys not only participated in more organized throwing activities than girls, but they also remebered practicing overarm throwing more frequently than girls. However, the differences in throwing perfor­ mance appear to be too great and seem to occur at too early an age to be completely attributable to the environmental variables [13]. The performance of throwing tasks tended to be stable across the longitu­ dinal perspective. This stability reflects a greater genetic influence on performance [1]. The purpose of the present study was to investigate selected kine­ matic variables in running at maximal speed and overhand throwing of 8-year-old children. 71 Methods The subjects were 60 healthy local elementary-school children, of which 33 were boys and 27 girls. All children were 8-year-old at the time of measurement. Both the children and their parents were informed about the nature of this study, and parental written consent was obtained. Testing procedures. The local school stadium was used for record­ ing the kinematic characteristics of running and overhand throwing. Two testing sessions were required to complete testing of the given subjects in running and overhand throwing. In the first session the kinematics of running at maximal speed was recorded. During data recording each child was first videotaped while standing on the run­ ning course holding a meter stick which served as a linear scale. In order to help to locate joint centers in later analysis, joint markings were placed on the joint centers of the limbs. Three trials of each child were recorded with the help of a "Panasonic" videocamera which was placed during the taping to the left of the child. The camera objective was placed perpendicular with the running course. The distance be­ tween the camera and the child was 20 meters. In the second session the kinematics of overhand throwing was recorded. The videotaping conditions were the same as in the first session. Each child performed 3 trials with a tennis ball (weight 150 g). The task of the child was to throw as far as possible. Data analysis was carried out with the help of Human Movement Kinematic Analysis computer programme "KINEX". Two-dimensional videotape analysis was employed to ob­ tain the kinematic characteristics. The videotape data were processed by computer programme which provided frame-by-frame stick figure computer graphics. The 40 msec frame-by-frame interval was used in data analysis. The videotape data were analyzed using the equipment located in the Kinesiology Laboratory, Tallinn Pedagogical University. All the recorded characteristics were expressed as means and stan­ dard deviations. T-test was used for establishment of gender differ­ ences. Results The mean height and weight of boys and girls are presented in Table 1, There were significant differences between boys and girls in respect to body weight. Table 2 outlines the kinematic parameters of running. There were no significant differences regarding the step length, duration of support and flight phases and loss of horizontal ve­ locity during support phase. However, boys surpass girls significantly in running speed. The kinematic parameters of overarm throwing are presented in Table 3. There were significant differences in favour of boys in all recorded parameters. 72 T a b l e 1 Anthropometric parameters Parameter Boys Girls M SD M SD Height (cm) 135.1 6.2 134.1. 7.3 Weight (kg) 31.5 4.3 28.7 3.4* * p < 0.05 T a b l e 2 Kinematic parameters of running Parameter Boys^ M SD M SD Running speed (m/s) 5.3 0.5 5.0 Step length (cm) 138.9 14.4 134.9 12.5 Support phase time (s) 0.154 0.2 0.148 0.5 Flight phase time (s) 0.120 1.4 0.116 2.2 Loss of horizontal speed (m/s) -0.63 0.1 -0.63 0.08 * p < 0.05 Tab l e 3 Kinematic parameters of overhand throwing Parameter M SD M SD Throwing result (m) 23.3 6.2 17.5 4.4* Horizontal ball velo­ city (m/s) 16.3 2.4 13.3 2.6* Angle of ball release (degrees) 28.2 3.7 24.9 5.2* Throwing time (s) 1.32 0.1 1.21 0.4* Swing phase time (s) 0.92 0.8 0.73 0.3* Throwing phase time (s) 0.38 0.2 0.48 0.1* * p < 0.05 Discussion The results of this study provide evidence for gender differences in the overhand throwing kinematics in prepubertal children. Regarding the running kinematic pattern, no gender differences were found. As in many previous studies, the significant advantage of boys in overhand throwing kinematics [6, 7, 9,10] was confirmed. 10 73 o o О The literature on motor development implies that children have mastered the fundamental movement pattern by the age of five or six years [3, 4]. When examining the maximal speed running kinematic parameters both in 8-year-old boys and girls, it become evident that the general characteristics of running do not differ. No support to this finding has been found in previous studies [2,8] because boys and girls have been studied separately. Only Fortney [5] has examined the gender differences in maximal speed running kinematics in 2 to 6- year-old children and the results have revealed that there were gender differences in parameters associated with the movement of the swing leg. The results of the given study do not support these findings because the movement of different body segments was not studied. The greater running speed of boys in the present study is in agreement with earlier researchers, who suggest that boys tend to run about one- third foot per second to one foot per second [15] faster than do same- age girls. Regarding the kinematics of overhand throwing, it become evident that clear gender differences appeared between 8-year-old boys and girls. These results support the findings of earlier studies [6, 10, 14] where the gender differences in overhand throwing were found. The throwing distance and horizontal ball velocity are two more frequently studied kinematic parameters of overhand throwing. The present investigation revealed that boys surpass girls in horizontal ball velocity by 3 m/s. These data supported other studies [6, 12] in which sex differences in ball velocities were examined. The throwing distance differences found in the present study are closely related with the horizontal ball velocity differences and with other kinematic parameters. One common explanation for developmental differences between sexes is that girls do not have the same amount of experience in overarm throwing as boys [12]. However, Nelson et al. [9] reported that although the biological factors are not the major contributors of gender differences in throwing, these factors have a certain influence to the throwing performance. In summary, our results indicate gender differences in kinematic characteristics of overhand throwing. In these characteristics 8-year- old boys surpass significantly the same-aged girls. In running kine­ matics gender differences were not found. Future research is needed to examine which factors contribute to sex differences in fundamental movement kinematics of elementary school children. REFERENCES 1. Branta, C., Haubenstricker, J., Seefeldt, V. Age changes in motor skill dur­ ing childhood and adolescence. — Exercise and Sport Science Reviews, 1984,12,467-520. 74 2. Brown, E. W. Biomechanical analysis of the running patterns of girls three to ten years of age. Unpublished doctoral dissertation. University of Oregon, 1978. 3. DeOreo, K., Keogh, J. Performance in fundamental motor tasks. — A Textbook of Motor Development. Ed. C. Corbin. Dubuque IA: Brown, 1980. 4. Es penschade, A. S., Eckert, H. M. Motor development. 2nd ed. Merill: Columbus, OH, 1980. 5. Fortney, V. L. The kinematics and kinetics of the running pattern of two- , four-, and six-year-old children. — Res. Quar. Exer. Sport, 1983, 54, 126-135. 6. Haiversen, L. E., Roberten, M. A., Langendorfer, S. Development of the overarm throw: Movement and ball velocity changes by seventh grade. — Res. Quar. Exer. Sport, 1982,53,198-205. 7. Haubenstricker, J., Seefeldt, V. Acquisition of motor skills during child­ hood. — Physical activity and well-being. Ed. V. Seefeldt. Res ton, VA, American Alliance for Health, Physical Education, Recreation and Dance. 1986, 41-102. 8. Miyamaru, G. Development of motor pattern in preschool boys, running pattern and jumping pattern. — Japanese Society of Biomechanics. Tokyo: Science of Human Movement, Kyorin Book Company Ltd., 1976, 2, 96- 114. 9. Nelson, J. K., Thomas, J. R., Nelson, K. R., Abraham, E C. Gender differ­ ences in children's throwing performance: biology and environment. — Res. Quar. Exer. Sport, 1986,57,280-287. 10. Nelson, R. N., Thomas, J. R., Nelson, J. K. Longitudinal changes in throw­ ing performance. — Res. Quar. Exer. Sport, 1991,62,105-108. 11. Roberten, M. A. Stability of stage categorizations across trials: implica­ tions for the "stage theory" of overarm throw development. — J. Hum. Mov. Stud., 1978,3,45-59. 12. Roberten, M. A., Halverson, L. E., Langendorfer, S., Williams, K. Longitudinal changes in children's overarm throwing ball velocities. — Res. Quar. Exer. Sport, 1979,50,256-264. 13. Thomas, J., French, К. E. Gender differences across age in motor perfor­ mance: A meta-analysis. — Psychological Bulletin, 1985, 98,260-282. 14. Thomas, J. R., Michael, D., Gallagher, J. D. Effects of training on gender differences in overhead throwing: A brief quantitative literature analy­ sis. — Res. Quar. Exer. Sport., 1994,65, 67-71. 15. Wohlwill, J. F. The study of behavioral development. New York: Academic Press, 1973. 1 0 * 75 RESTORATION OF NORMAL FUNCTIONAL ACTIVITIES AFTER EXERCISE A. Viru Institute of Exercise Biology, University of Tartu, 18. Ülikooli Street, Tartu, EE2400 Estonia The aim of the brief review is to indicate the factors influencing or controlling the transition from the exercise level of functional activities to the resting level. Various phenomena of the postexer- cise recovery are discussed and plotted against the activities of the regulatory mechanism and intrinsic pecularities within the system. Introduction Exercise performance is followed by a recovery period. This is the time when the following tasks have to be accomplished: (1) transition from the exercise level of functional activities to the resting level, (2) normalization of homeostatic equilibriums, (3) replenishment of energy resources together with a temporary supercompensation for them, (4) reconstructive alterations, particularly in regard to cellular structures and enzyme systems. An integral of all recovery processes is the restoration of the initial level of working capacity of the organism. The first two tasks are actualized within minutes or in particular cases, within hours. The corresponding processes constitute the stage of rapid recovery. The actualization of other tasks consumes more time and thereby the stage of delayed recovery follows. However, the term "delayed" does not mean that the onset of replenishment of energy stores or of the reconstructive alterations is necessarily delayed. The realization of these tasks is delayed. This review has been composed in order to discuss the phe­ nomenology of the postexercise restoration of functional activities. In part the abolishment of oxygen debt was considered the mam rea­ son for maintaining functional activities over the resting level during a certain time after exercise [54]. However, the recovery phenom­ ena cannot be completely explained solely by the "postexercise con­ sumption of extra oxygen". Therefore various influences and control mechanisms have to contribute to the functional changes in the stage of rapid recovery. 76 Oxygen transport system Cessation of muscular contractions at the end of exercise or var­ ious kinds of physical work cause a change in regulatory influences: the regulatory actions of central command and proprioceptive im­ pulses drop out. As a result, rapid changes occur in the functions of organs responsible for oxygen transport, despite the persisting high demand for oxygen supply of skeletal muscles only just having acted. These transitory changes are opposite to the initial adjustments at the beginning of exercise in the direction of change, but similar to the general pattern: first there is a rapid and then a gradual decre­ ment of functional activity. While the rapid changes within the first 1-2 minutes express the cessation of the actions of central command and proprioceptive influences, the second gradual and often undu­ lated decrease may be explained by the reduction of influences from metaboreceptors and of hormonal influences. Differently from the initial adjustments, exercise intensity is a factor that retards the rate of postexercise changes. After highly intensive exercise during the first 5-10 s the heart rate may not change and then the following de­ crease is not characterized by so steep a slope as after less intensive exercise [45, 90, 112]. A possibility of a regulatory inertia seems to exist as well: the duration of exercise may be overriden by the persist­ ing excitement of the cardiac center, stimulating the sino-atrial node through sympathetic discharge. A further increase in the heart rate was noticed during the first 5-8 s in 65% of persons after 15-s cycling at maximal possible rates [45]. After weight-lifting exercise the duration of cardiac cycle further diminished within 3-7 s. The obtained levels were after clean and jerk 145 ± 3 and after two-hand snatch 134 ± 2 beats per min. A pronounced increase in the duration of the cardiac cycle, a respective decrease of the heart rate, began in the second half of the first min af­ ter putting the bar on the floor [99]. The duration of the weight-lifting exercise (4-7 s) was too short for pronounced hormonal changes. On­ ly to a modest extent the muscle metaboreceptors might influence the heart rate just after the end of exercise. It is more likely that there exists a prevalent influence from respiration during weight-lifting and after putting the bar on the floor as well as from changes in venous re­ turn, related to corresponding pecularities in respiratory movements. A possibility of a regulatory inertia seems to exist as well: the dura­ tion of exercise may be overriden by the persisting excitement of the cardiac center, stimulating the sino-atrial node through sympathetic discharge. The postexercise dynamics of heart activity are characterized by enhanced respiratory arrhythmia as well as by pronounced waves in the duration of the cardiac cycle corresponding to the third waves in blood pressure (Fig. 1). This picture is revealed in association with 77 a steep slope of the heart rate decrement and mainly in well-trained persons [45]. An increased rate of recovery of heart frequency was found in trained persons also after exercise with increasing intensity up to the individual maximum [27]. It is likely that the steep slope of the heart rate expresses not only the decrement of metabolic influence but also a strong parasympathic influence. Mostly in well-trained persons after the exercise the heart rate decreases from 20-40 s to values below the initial [45,64,94]. This can be considered an expression of "hypothalamic tuning" of automatic nervous influences. By Gellhorn [41], autonomic imbalance due to the prevalence of sympathetic or parasympathetic actions causes increased sensitivity to change in the opposite direction. The previous prevalence of sympathetic influence during exercise sensitizes the parasympathetic effects. As a result the heart rate decreases below the initial values. However, this change does not appear after very strenuous exercise. Instead of that after strenuous exercises and in most cases in untrained persons the heart rate may stabilize to a level of 5-20 beats per min higher than the initial [45, 64,94]. After a 5-min exercise the heart rate decreased exponentially to the initial level during the first postexercise minute despite the maximal noradrenaline level in the blood at the same time. Therefore it was suggested that the rapid heart rate recovery after exercises is related to the increased vagal tone rather than to the decrease in the activity of the sympatho-adrenal system [82]. Summing up, the following variants of heart rate postexercise dy­ namics were found (Fig. 2): (1) undulated process — a rapid decrease to values below the initial followed by normalization to the initial level, (2) aperiodic process with restitution of the normal heart rate within 1-2 min, (3) aperiodic process with stabilization of the heart rate on a level above the initial, (4) torpid process without any stabilization during the first 5 min (heart rate remains elevated for 20-30 min) [94]. By using various methods it was found that a rapid decrease of car­ diac output and stroke volume occurs within the first 1-2 postexercise minutes. Then a less abrupt decrease follows [23,24, 29,74]. The transition from exercise to rest is connected with a short-term drop in the intra-arterial pressure, often to values below the initial [32, 38, 55]. Already after 5-10 s a new increase in blood pressure takes place. The latter lasts approximately 20-40 s [55]. After that a gradual decrease in arterial pressure follows. The same dynamics were established in the mean arterial pressure using a non-invasive method for its continuous recording [31]. A secondary increase in stroke volume was found during 1-2 min after exercise. During this time period the peripheral resistance remained low and only later it increased gradually [29]. By using special equipment, the ausculatory recordings of blood 78 1 2 3 4 it ул 1 5 1 5 min Fig. 2. Four variants of heart rate postexercise dynamics [94]: 1— undulated process, 2 — aperiodic process with restitution of the normal heart rate within 1-2 min, 3 — aperiodic process with stabilization of the heart rate on a level above the initial, 4 — torpid process without any stabilization during the first 5 min. pressure were obtained over every 8-12 s. A comparison of the pat­ tern of ausculatory blood pressure during and after various exercises showed that after exercise maximal arterial pressure rises to levels higher than those recorded during exercise when the exercise du­ ration was 30-60 s and therefore insufficient for blood pressure to increase to the adequate level (Fig. 3). After cessation of exercises lasting for 3-5 min, maximal arterial pressure decreases without any secondary rise [103]. When the person was in a standing position, the blood pressure drop was common immediately after the end of 1-min cyclic exercise. The following rise in maximal pressure as well as the decrease in the heart rate were less pronounced than in the sitting position (Fig. 4). When the blood flow to legs was prevented by a bandage on the thighs, there was no immediate decrease in blood pressure and the postexercise increase was the same as in the sitting position [104]. Thus the immediate postexercise drop in arterial pres­ sure is related to the aggravated venous return due to the cessation of the muscle pump function. Already in the 1930s it was demonstrated that a circulatory collapse called "gravity shock" revealed during pro­ longed standing after intensive exercises. The phenomenon can be avoided by a pressure bandage on the thighs [79]. Differently from this mechanism a late müd hypotension may fol­ low within a period from 0.5 to 3 hrs after the end of exercise. It seems not to be due to an acute impairment of baroreflex function [14, 26, 91]. Prostaglandins produced by skeletal muscles and kid­ ney as a result of exercise may contribute to prolonged postexercise vasodilation [77]. 80 1 2 з 4 5 6 7 8 9 10 И 12 13 Fig. 3. Dynamics of heart rate (solid line) and arterial ausculatory pressure (maximal pressure—the upper broadline of the dotted area, minimal pressure — the lower broadline of the area). The onset and end of exercise are indicated by interrupted vertical lines. On the ordinate heart rate (beats per min) and arterial pressure (mm Hg). The time is indicated by min. On the left 1-min and right 5-min exercises performed at the same intensity [103]. 200 160 120 80 40 1 2 3 4 5 6 7 8 9 10 11 12 Fig. 4. Dynamics of heart rate and arterial auscultatory pressure during and after three 1-min cycling exercises performed at the same intensity [104]. On the left — person in sitting position after exercise, in the middle — person in standing position after exercise, on the right — person in standing position but immediately after the exercise a pres­ sure bandage on the thighs. The rise of pressure in the bandage up to 200 mmHg is indicated by the first arrow and the release of thighs from bandage by the second arrow. Other explanations see on Fig. 3. The transition of lung ventilafion and oxygen uptake from exercise level to resting level is usually described by a simple exponent: during the first 1-2 min the changes are faster than later on [48]. Immediately after the end of a 5-min cycling at moderate intensity the respiratory frequency and depth decreased in association with a reduced electrical activity of intercostal muscles [57]. The exponential curve may not be revealed after short-term highly intensive exercise or after static efforts. After cycling exercises per­ formed at the highest possible oxygen demand, the amount of oxygen corresponding to the lactate component constituted 37%, 49% and 44%, the "oxygen consumed during exercise 3%, 11% and 26% of the total oxygen demand respective to exercise duration of 10 s, 15-20 s, and 30-45 s [58]. The alactatic component of oxygen debt is considered to corre­ spond to the amount of O2 necessary for refilling the body's oxygen stores and for restoration of normal levels of ATP and phosphocre- atine. Resaturation of blood hemoglobin amounts to about 0.2 1 O2 after submaximal and 0.3 1 O2 after supramaximal exercises [5]. For resaturation of muscle myoglobin additional 0.1 and 0.21 O2 are necessary after submaximal and supramaximal exercises respective­ ly. Thus the total contribution from O2 store replenishment is 0.3 1 after submaximal and 0.5 1 after supramaximal exercises [10]. Data were presented indicating that phosphocreatine and ATP concentra­ tion decreases by 1.0 and 12.0 mmol • ng-1 in both the submaximal and supramaximal exercise [68]. The latter corresponds to an O2 cost of 0.6 1. Consequently, the alactic O2 debt has to be approximately 0.9-1.1 1 O2. A three times higher value of alactatic O2 debt was calculated for highly qualified sportsmen by a steeper slope of Vq2 after a supramaximal exercise [105]. There is no exact evidence that the replenishment of phosphocre­ atine store occurs during the time of repayment of the fast component of oxygen debt. A study of the rat leg muscle by phosphorus nuclear magnetic resonance demonstrated that phosphocreatine concentra­ tion rises to the initial level at the end of the recovery period in accordance with the normalization of Vq2 by muscle tissue [73]. Evidence was also provided demonstrating a dissociation between the kinetics of lactate removal and the slow component of the postex­ ercise oxygen uptake [21]. Neither the total oxygen debt nor the 'lactic debt' give exact mea­ sures of the amount of energy released in anaerobic processes [12, 46, 109]. The main arguments are: (1) increased body temperature alters the intensity of metabolism, (2) intensive function of myocardi­ um and respiratory muscles continuing after exercise, need additional energy, (3) altered muscle tone may cause changes in oxygen uptake, (4) changes in blood level of adrenaline, thyroxine and some other 82 hormones may alter the intensity of oxygen uptake and the ratio be­ tween oxidative phosphorylation and free oxidation, including free radical oxidation. Elevated temperature has been suggested to decrease phospho- lylative coupling efficiency in mitochondria [16]. As a consequence, more O2 would be required for a given amount of ATP to be syn­ thesized. The temperature effect is calculated to amount to 1.2 1 of oxygen during the first hour of recovery after submaximal and 0.6 1 supramaximal exercises when the exercise was performed in comfort­ able temperature [5, 6, 53]. Intensive function of the myocardium and respiratory muscles con­ tinuing after exercise need additional energy. It was calculated that the O2 cost of moving an additional blood volume through the circu­ lation is about 1.31 after submaximal and 0.71 for the first hour after supramaximal exercise. The ventilatory cost constitutes 0.1102 [5, 6, 53]. Noradrenaline infusion induced small changes in Vq2 dur­ ing electrically induced concentrations of the denervated canine gastrocnemius-plantaris muscle group in situ, but the arterio­ venous O2 content difference increased significantly. During post- contraction recovery, VQ was increased by 40% by noradrenaline in­ fusion. The ratio of net recovery Vq2 to the Vq2 during contraction period was significantly elevated by noradrenaline [42]. Accordingly the blockade of adrenergic influences by administration of propranol reduces the rate of O2 uptake during exercise and particularly dur­ ing the post-exercise recovery period [12, 21, 22]. Catecholamines, thyroxine and glucocorticoids can contribute to the increase in the Na+-K+ pump activity. These factors undoubtedly interact to affect the excess post-exercise oxygen consumption. Lactate dynamics and pH values in postexercise recovery Postexercise lactate values are widely used for evaluation of the participation of anaerobic glycolysis in the energy attaining of strenu­ ous exercises. However, during exercise lactate accumulates because the increase in the lactate disappearance rate lags behind the in­ crease in the lactate appearance rate [17]. Therefore the amount of resynthesis of ATP at the expense of anaerobic glycolysis will be underestimated if the calculations are based on the lactate accumula­ tion in the blood or in the postexercise oxidation of lactate ("lactate debt"). One must take into consideration also the various pathways of the fate of pyruvate formed during exercise: besides the oxidation 1 1 * 83 of pyruvate and the transformation to lactate, one part is used for alanine synthesis. Pyruvate determination does not help because the measured pyruvate gives only its residual amount in a moment of time. Nevertheless, these sources of errors will not make the use of lactate levels and lactate debt meaningless in evaluating the anaerobic energy production, because in supramaximal exercise the largest part of pyru­ vate is transferred to lactate and lactate production greatly exceeds its elimination. Only the quantitative estimation of the energy released in anaerobic glycolysis may be not exact. After exercise a part of both the formed pyruvate and lactate is used for glycogen resynthesis in exercised muscles. After supramaximal exercises causing blood lactate levels of 10-16 mmol • l-1 and muscle lactate content of 25 mmol • kg-1 the proportion of lactate used for the resynthesis of glycogen has been estimated at 75% [52], 50% [4], and 13-27% [11]. The rate of lactate removal during recovery is directly related to the lactate concentration at the end of exercise [62]. Using a knee- extensor exercise model inducing exhaustion within 2-4 min, it was found that at the end of exercise, femoral vein plasma concentration of lactate is only half of that accumulated in the muscle (the muscle-blood gradient was 18 mmol • l-1), but 3 min into recovery, the difference was reduced to 5 mmol • l-1, and it was nil after 10 min of recovery. During 1 h of recovery as much as 82% of the lactate left the muscle as lactate via the blood stream [11]. After a 4-min exhaustive exercise the lactate release from working muscle gradually decreased. This process continued for at least 8- 15 min [63]. After 3-min exhaustive cycling, blood lactate increased during the first 10 min while a pronounced drop occurred in the muscle lactate concentration. Thereafter lactate decreased also in the blood. In the period of 80 to 60 min after exercise the lactate concentrations in muscles will approximately equal [28]. In the blood the postexercise lactate curves could be fitted to a bi-exponential time function, consisting of a rapidly increasing and a slowly decreasing component [34,40]. A comparison of lactate pattern after 3-min and 60-min exercises showed that with exercise duration the values of velocity constants of lactate increase and decrease were reduced [36]. In exercise intensities over the anaerobic threshold, the blood lactate concentration increased with the prolongation of exercise duration from 3 to 6 min, but the constants of kinetics for both postexercise increase and decrease of lactate concentration decreased [37]. The postexercise lactate kinetics is determined by the ability of tissues to utilize lactate as well as by factors limiting this process [35]. During the first 5 min of recovery after cycling with increasing intensity, the pyruvate concentration progressively increased in the blood. The lactate/pyruvate ratio decreased [107]. It has to be estab­ 84 lished if the decreased lactate/pyruvate ratio is a general phenomenon appearing immediately after the cessation of muscle contraction, and if it indicates a relative decrease in the pyruvate conversion by the corresponding metabolic pathways. As a result of intensive anaerobic glycogenolysis an accumulation of hydrogen ions appears in the muscles [50,87,88] and in the blood [50,67,77]. The changes in pH values after exercise are parallel to the changes in lactate concentrations [67, 87,88]. An intensive anaerobic exercise of 4 min duration resulted in a decrease of the thigh muscle pH from 7.15 ± 0.01 to 6.57 ± 0.04 and of the blood from 7.39 ± 0.04 to 7.04 ±0.03. During the first 5 min of recovery the decrease continued and then the pH values began to increase [3]. After another 4-min exhaustive exercise the low pH persisted for 4 min in arterial blood and then began to increase. In venous blood a graudal increase began from the first postexercise minute. Both values returned to a level close to the initial within 20 min [50]. Cycling at high intensity (mean heart rate 192) until exhaustion resulted in a pronounced drop of pH values in the m. quadriceps (total muscle pH from 7.08 ± 0.03 to 6.64 ± 0.12), intracellular pH (from 7.00 ± 0.06 to 6.45 ± Ö.09), femoral venous blood (from 7.08 ± 0.06 to 6.93 ± 0.06) and arterial blood (from 7.27 to 7.14). Muscle lactate increased up to 22.0 ± 2.6 mmol/kg (intracellular lactate to 29.1 ± 3.4) and femoral venous blood lactate up to 17.5 ± 5 mmolA. 20 min after exercise the muscle lactate remained elevated but both total muscle and intracellular pH were normal. The pH value of femoral venous blood normalized within 20 min. 30 min after exercise, significantly elevated pH values were found in comparison with the pre-exercise values. At the same time the blood lactate was insignificantly lower than the initial level [88]. In most cases lactate concentrations normalize within 30-60 min after intensive exercises [50, 67, 88]. Moderate exercise performed during recovery caused a faster elim­ ination of lactate from the muscle [13,15, 51]. First it was supposed to be related to enhanced perfusion [51]. However, the stimulation of the oxidation rate contra its decline may have significance as well. Anyway, mild exercise following a strenuous one enhanced lactate ox­ idation [47]. There is previous evidence that activity increases lactate removal also from the blood [60, 81]. Lactate disappearance after exercise at VQzmax level was intensified by exercise at 40% VQ2max but not by exercise at 65% VQ2max [110]. However, other stud­ ies indicated that recovery exercise at 65% VQ2max [51] or at 60% VQ^max [43] is optimal for speeding up lactate removal. After a 10- min exercise at 90% VQ2max, active rest slightly below the anaerobic threshold improves the lactate removal rate compared to complete rest or active rest above the anaerobic threshold [80]. 85 Endocrine system A number of studies on blood levels of hormone during the first 10- 20 min of postexercise recovery revealed the continuation of exercise- induced change before the opposite change occurs. Thus the en­ docrine response to exercise may be more prolonged than the exercise itself (Fig. 5A). In other cases opposite changes were found to begin just after the end of exercise (Fig. 5B). These opposite changes do not mean a fast normalization of hormone levels in the blood. Quite often they reach concentrations significantly differing from the initial values. Thus the exercise-induced rise or drop may by changed by a decrease or an increase, respectively. The new hormone level may now persist for a long time. There are cases of a secondary rise in the hormonal level after a certain time of rest. Of course, there are also cases of gradual normalization of the hormone level to the normal concentration. The hormone changes in the recovery period express, obviously, not only the inertia of regulation in regard to exercise- induced changes, and the following normalization of the endocrine function. The regulation of metabolic processes during the recovery period may require specific changes in hormone levels. During the first minute after the end of 5-min cycling exercises the noradrenaline concentration rose a little. During the following 10 min the hormone concentration decreased rapidly. Two months of training accelerated, but the following two months of detraining decelerated the restitution rate of the noradrenaline level. Increase in the power output during exercise from 1480 kpm • min-1 to 1920 kpm • min-1 slowed down the disappearance of noradrenaline from circulation [44]. A rapid decline in the adrenaline concentration after short-term exercises has been found by other investigators [61]. After prolonged exercise, high levels of catecholamines may persist for many hours or even for days. Both adrenaline and noradrenaline concentrations were increased for 2 hrs after 80-min exercise at 75% of Vq2 max [9]. After a marathon race the elevated level of adrenaline persisted for at least 24 hrs [78]. 24 hrs after the 24-h endurance run or triathlon competition the blood levels of free an sulpated cate­ cholamines were elevated [86]. During a 6-day cross-country skiing as well as in the evening, the blood levels of catecholamines were el­ evated, but catecholamine response to the ergometer test, performed immediately after skiing, was normal. Eleven days after the hike the noradrenaline concentration was above the initial level by 25% [106]. After short-term exercises the increase in the blood Cortisol con­ centration continues within the first 5-30 min [2, 3, 39]. This may be due to the inertia of the activation mechanism or of the secretory response of the adrenal cortex. The latter possibility was revealed 86 "n8g- ml 1 30 Л 20 / \ 10 J-li 1 900kpm-mn г r -}600kpm-mn" -30 -10 0 10 20 30 40 50 min Fig. 5А Dynamics of somatotropin concentration in the blood after 20-min exercises of various intensities [93]. Somatotropin ng ml-1 Prolactin mU ml-1 Lutotropin 800 somatotropin ng mli -l I prolactin 600 400 200 \~f-4 lutropin EXERCISE [ 30 90 120 180 240 min Fig. 5B Dynamics of somatotropin (solid line), prolactin (interrupted line), and lutropin (interrupted short lines) during and after 2-hour cycling exercise on ergometer [101]. 87 in a study demonstrating the highest corticotropin level immediately after, but the highest Cortisol level 15 min after 1-min cycling at 120% Vo2max [19]. The elevated blood Cortisol after exercise has been shown to be related to the decreased rate of hormone elimination from blood plasma as well [33]. After a 30-min exhaustive exercise the blood Cortisol level rose during the first 30 to 60 min, and then de­ clined. The resting level was obtained within 90 to 120 min [92]. After 80-min exercise at 70% VQ2max a transient increase in the plasma Cortisol concentration lasted for one hour after exercise [76]. A heavy anaerobic exercise (running 3 x 300 m) was followed by a high level of Cortisol in the blood that persisted for 3 hrs. Then a drop in the Cortisol concentration followed. 6 hrs after the end of exercise it was substantially below the initial level [72]. A decrease in the glucocorticoid level following the preceding pos­ texercise increase was confirmed in a number of studies. For example 3-6 hrs after 13-14 km run a low Cortisol level was observed [2]. After 2-h exercise at 60% VQ2max a decreased activity of the pituitary- adrenocortical system was established by levels of both corticotropin and Cortisol below the initial within 6-24 postexercise hours. There were no systematical differences between data obtained from un­ trained persons and from well-trained sportsmen in endurance events [102]. Low levels of Cortisol were found 24 hrs after marathon race [78], and running for 100 km [66]. 1, 2 and 4 days after running for 34 km, blood Cortisol was insignificantly and, 8 days later, significantly below the initial values [30]. In rats the corticosterone content in the blood plasma and in the adrenals remained augmented during 5 days following the 30-min swimming (Fig. 6). The peak values were observed after 2 days in the adrenals and after 5 days in the plasma. One day later, repetition of the same exercise did not elicit any response. After 2 days the response was inversed. Following 3 to 5 days after the first exercise the response to the new exercise was exaggerated [100]. Is the latter a reflection of supercompensation for biosynthetic activity in the cells of the fascicular zone of the adrenal cortex? Anyway, an elevated content of ascorbic acid in the adrenal tissue was found several days after exercise [84]. Exercise is followed by a rapid increase in the blood level of insulin [20, 83, 85] (Fig. 7). This change is so rapid that any measurement of insulin concentration, not carried out while the subject is still ex­ ercising, may be misleading in regard to the detection of an insulin drop during exercise [83]. The concomitant increase in the C-peptide level in the blood indicates that insulin secretion increases just after the end of exercise [111]. After a 100 km run the insulin level in the blood was still increased 88 ß 100 g tissue 1 2000 Adrenal corticosterone content 1600 1200 800 ß 100 ml 1 Blood plasma corticosterone concentration ушшШшшш/шт 0 1 2 3 4 5 Fig. 6. Adrenal and blood plasma corticosterone concentration in rats after a 30-min swim [100]. Open circles — basal level; rhomboids — level after an additional 30-min swim; striated area — level of control group. Time is indicated in days. 24 hrs later [66]. Running of 34 km was followed by a decreased insulin level one day later [30]. The glucagon level decreases gradually from the highest concen­ tration just after the end of exercise [25, 92]. Elevated glucagon values persisted for 90-120 min after 30-min cycling until exhaustion [20] (Fig. 7). 1, 2, 4 and 8 days after running of 34 km the glucagon concentration was close to the initial level [30]. In most cases the recovery period is characterized by a rather 12 89 IR1 I 1 150 - ' ! /IU ml- I У 100 - 20 - Л 1 / 1 / At 50 - 10 - !i 1 1 [EXERCISE] 1 \ 30 60 90 120 mill Fig. 7. Dynamics of insulin (closed circles) and glucagon (open circles) in blood plasma of men after an exhaustive exercise on the bicycle er- gometer [20]. rapid decrease in the somatotropin concentration in the blood to normal values if the hormone level was augmented during the exercise [25, 92, 93]. The rebound time is dependent on the fitness level. After the cessation of a 30-min exhaustive exercise the somatotropin concentration returned to the resting level within 30 min in fit persons, but continued to increase for 60 min before declining in those who were unfit [92]. A postexercise increase in the blood somatotropin level was observed mostly after comparatively short-term exercises: after 20-min aerobic exercise or after 7 repetitions of 1-min anaerobic exercise [97, 98] or after intermittent weight-lifting exercises [96]. An anaerobic running exercise 3 x 300 m induced even in trained persons a persistently high somatotropin level during the first hour of restitution. Subnormal values were found 6,24 and 72 hrs later [2]. In athletes the blood level of somatotropin was higher on the night after daytime training exercises than during the control night [1]. Usually the pituitary-testicular system does not respond until the recovery period. Within the first 6 hrs of restitution after various exer­ cises for improved endurance, a gradual drop in the blood testosterone [2,72,102] (Fig. 8) and androstenedione [2,72] occurs. The low levels of both compounds may persist for at least 3^4 days [2, 30,66]. 90 90-min running 45-min running Running 24 hn Fig. 8. Blood plasma testosterone levels after running for 45 and 60 min (13 to 14 km and 21 km respectively) [72]. Prolonged running (15 to 42 km) caused a decrease in the plasma testosterone concentration. The longer the run, the more time it took before the testosterone concentration returned to precontest levels [65]. In rats, short-term swimming with a high additional load (13% of body weight) caused a slight increase in the blood testosterone level that was followed during the first 2 hrs of restitution by a decrease in the hormone level. 4 hrs after the exercise a rise in the hormone con­ centration was detected, exceeding the resting level by 1.5 to 2.5 times [69]. This exercise bout caused postexercise rises in testosterone, an- drostenedione and estradiol content in the blood, skeletal muscles, and the myocardium. In skeletal muscles the hormone content was close to normal after 2 hrs, but increased after 48 hrs. 72 hrs after the exercise a decrease was observed in the androstenedione and estra­ diol content and a further increase in the testosterone content. The number of androgens-binding sites was increased by 20% 2 hrs and by 80% 72 hrs after exercise [95]. Immediately after the marathon run, increased thyroid activity was evidenced by elevated blood level of free thyroxine, free triiodothy­ ronine and thyrotropin. Free thyroxine remained elevated 1 h later as well. 22 hrs after the race the thyrotropin concentration was de­ creased, thyroxine and triiodothyronine level were close to pre-race 12* 91 values. Comparison of the changes of free thyroxine or free triiodothy­ ronine to free reverse triiodothyronine indicated that 22 hrs after the race still a favoured conversion of active hormones to inactive reverse triiodothyronine exists [89]. In rats 10-min swimming with additional load equal to 10% of body weight induced an increase in the thyroxine and triiodothyronine blood level for 48 hrs, with peak values for 1.5 hrs after the end of exercise. This response was observed even in rats made hypothyroid by repeated injections of mercasolil. The peak values were revealed 48 hrs after exercise [70]. Substantial changes in the endocrine system during the postexer­ cise recovery period are evidenced by altered responses to repetition of the same exercise or to test exercise. In swimmers the noradrenaline, adrenaline, corticotropin, Cortisol and somatotropin responses to a 100 m swim, repeated 1 h after the first swim, were suppressed in comparison with responses to the first exercise bout. When swimming for 1500 m was repeated, noradrenaline and adrenaline responses were exaggerated, Cortisol and somatotropin responses decreased. In both exercises the insulin response did not change. Increases in lac­ tate, glycerol and FFA level were more pronounced after the second repetition of these exercises [108]. When highly qualified weight-lifters performed two strength train­ ing session in one day, an increase in serum Cortisol as well as in total and free testosterone concentrations was observed only after the second training session. One hour after the termination of the af­ ternoon session a decrease followed in the levels of three hormones. Instead of an increase, the studied hormones decreased in response to the morning session. It was suggested that the diurnal variations might mask the exercise-induced changes during the morning session [56]. However, summation of the effect of the training session might also have an essential role. This possibility is indicated by a less pro­ nounced increase in the lactate concentration and also by a more pronounced impairment of the maximal isometric force, the maximal rate of force development and relaxation-time after the second than the first training session [56]. Conclusion Immediately after cessation of muscular concentrations a drop out of regulatory action of central command and proprioceptive influences cause rapid changes in the functions of organs responsible for oxygen transport. Rapid transitory changed occur despite the persisting of an increased level of various metabolites in muscles and blood. In heart 92 activity the onset of the rapid change may be postponed for 5-15 s by a possible regulatory inertia after very intense exercises. Later the changes are influenced by hypothalamic tuning of Sympathie and parasympathic influences. The cardiovascular changes are influenced also by a short-term fall in the intra-arterial pressure related, likely, to the drop out of the effect of "muscular pump" on the venous return of blood. In the recovery period the hormone changes may depend on the inertia of regulation but also on the need for specific regulation of metabolic processes during the recovery period. The rapid increase of blood insulin level as well as the altered ratio between catabolic and anabolic hormones concern the latter. REFERENCES 1. Adamson, L., Hunter, R. W., Ogurremi, О. O., Oswald, I., Percy-Robb, I. W. Growth hormone increase during sleep after daytime exercise. — J. Endocrin., 1974, 62,473-478. 2. Adlercreutz, H., Härkönen, M., Kuoppasalmi, K., Kosunen, K., Näveri, H., Rehunen, S. Physical activity and hormone. — Adv. Cardiol., 1976, 18,144-157. 3. Allsop, E, Cheetham, M., Brooks, S., Hall, С.M .,Williams, C. Continuous intramuscular pH measurement during the recovery from brief maximal exercises in man. — Eur. J. Appl, Physiol., 1990,60,465-470. 4. Ästrand, R O., Hultman, E., Juhlin-Dannfeldt, A., Reynolds, G. Disposal of lactate during and after strenuous exercise. — J. Appl. Physiol., 1986, 61, 338-343. 5. Ästrand, E O., Rodahl, К. Textbook of Work Physiology. 3rd ed. New York: McGraw-Hill Book Co, 1986. 6. Bahr, R., Maehlum, S. Excess post-exercise oxygen consumption. A short review. — Acta Physiol. Scand., 1986,128, suppl. 556,99-104. 7. Bahr, R, Ingnes, I., Vaage, О., Sejersted, О. M., Newsholme, E. A. Effect of duration of exercise on excess postexercise O2 consumption.—J. Appl. Physiol., 1987, 62,485-490. 8. Bahr, R., Hansson, P., Sejersted, О. M. Triglyceride/fatty acid cycling is increased after exercise. — Metabolism, 1990, 39, 993-999. 9. Bahr, R., Hostmark, A., Newsholme, E. A., Gr0nner0d, O., Sejersted, О. M. Effect of exercise on recovery changes in plasma levels of FFA, glycerol, glucose, and catecholamines. — Acta Physiol. Scand., 1991,143, 105-113. 10. Bangsbo, J., Gollnick, E D., Graham, Т. E., Juel, C., Kiens, В., Mizuno, M., Saltin, B. Anaerobic energy production and O2 deficit-dept relationship during exhaustive exercise in humans. — J. Physiol., 1990, 442, 539-559. 11. Bangsbo, J., Gollnick, E D., Graham, Т. E., Saltin, B. Substrates for muscle glycogen synthesis in recovery from intense exercise in man. — J. Physiol., 1991,434,423-440. 93 12. Barnard, R. J., Foss, M. L. Oxygen dept: effects of beta adrenergic block­ ade on the lactacid and alactacid components. — J, Appl. Physiol., 1969, 27,813-816. 13. Beicastro, A. N., Bönen, A. Lactate acid removal rates during controlled and uncontrolled recovery exercise.—J. Appl. Physiol., 1975,39,932-936. 14. Bennett, T. G., Wilcox, R. G., MacDonald, I. A. Post-exercise reduction of blood pressure in hypertensive man is not due to acute impairment of baroreflex function. — Clin. Sei., 1984, 67, 97-103. 15. Bönen, A., Beicastro, A. N. Comparison of self-selected recovery methods on lactate acid removal rates. — Med. Sei. Sports, 1976, 8,176-178. 16. Brooks, G. A., Hittelman, K. J., Faukler, J. A., Beyer, R. E. Temperature, skeletal muscle mitochondrial functions, and oxygen debt.—Am. J. Phys­ iol., 1971, 220,1053-1059. 17. Brooks, G. A. Anaerobic threshold: review of the concept and directions for further research. — Med. Sei. Sports Exerc., 1985,17,22-31. 18. Bullen, В. A., Skirinar, G. S., Beitins, I. Z., Carr, D. В., Reppert, S. M., Dotson, С. O., Fencel, M. de M., Gervino, E. V., McArthur, J. W. Endurance training effects on plasma hormonal responsiveness and sex hormone excretion. — J. Appl. Physiol., 1984, 56,1453-1463. 19. Buono, M. J., Yeager, J. E., Hodgdon, J. A. Plasma adrenocorticotropin and Cortisol responses to brief high-intensity exercises in humans. — J. Appl. Physiol., 1986, 61,1337-1339. 20. Böttger, J., Schiein, E. M., Faioona, G. R., Knöchel, J. R., Myer, R. И. The effect of exercise on glucagon secretion. — J. Clin. Endocrin., 1972, 35, 117-125. 21. Cain, S. M. Exercise O2 debt of dogs at ground level and altitude with and without /З-block. — J. Appl. Physiol., 1971, 30, 838-843. 22. Cain, S. M., Chapler, С. K. Effects of norepinephrine and a-block on O2 uptake and blood flow in dog hindlimb. — J. Appl. Physiol., 1981,51, 1245-1250. 23. Cerretelli, P., Piiper, J., Mangio, F., Cuttica, F., Ricci, R. Circulation in exercising dogs. — J. Appl. Physiol., 1964,19, 29-32. 24. Cerretelli, P. Readjustments in cardiac output during the onset of exercise and recovery. — J. Appl. Physiol., 1966,21,1345-1350. 25. Conlee, R. V.,H ickson, R. G., Winder, W. W., Hagberg, J. M., Holloszy, J. O. Regulation of glycogen resynthesis in muscle of rats following exercise. — Am. J Physiol., 1978, 235, R145-R150. 26. Convertino, V. A., Adams, W. C. Enhanced vagal baroreflex response during 24 h after acute exercise. — Am. J. Physiol., 1991, 260, R570- R575. 27. Darr, К. С., Bassett, D. R., Morgan, B. J., Thomas, D. R Effects of age and training status on heart rate recovery after peak exercise. — Am. J. Physiol., 1988,254, H340-H343. 28. Dimant, В., Karlsson, J., Saltin, B. Muscle tissue lactate after maximal exercise in man. — Acta Physiol. Scand., 1968,72,383-384. 29. DiBello, V., Santoro, G., Cini, G., Pentimore, F., Ginanni, A., Romano, M. F., Giusti, V. Cardiovascular adjustments induced by training evaluated during semisupine isotonic exercise and recovery period: An echocardio- graphic study. — Int. J. Sports Med., 1987,8,407^414. 94 30. Dufaux, В., Assmann, G., Order, U., Holderath, A., Hollmann, W. Plasma lipoproteins, hormones, and energy substrates during the first day after prolonged exercise. — Int. J. Sports Med., 1981,2,256-260. 31. Epler, M., Viru, A., Kurrik, E. On dynamics of arterial pressure and heart rhythm in short-term physical exercises. — Conference on Sports Physiology. Tiflis, 1960,224-226 (in Russian). 32. Eskildsen, P., Götsche, H. E., Hansen, A. T. Measuring intraarterial blood pressure during exercise. — Acta Med. Scand., 1950, 138, suppl. 239, 245-250. 33. Few, J. D. Effect of exercise on the secretion and metabolism of Cortisol in man. — J. Endocrin., 1974,62,341-353. 34. Freund, H., Zouloumin, P. Lactate after exercise. I Evolution kinetics in arterial blood. — Eur. J. Appl. Physiol., 1981,46,121-133. 35. Freund, H., Oyono-Enguelle, S., Heitz, A., Marbach, J., Ott, С., Zouloumi- an, P., Lantpert, E. Work rate dependent lactate kinetics after exercise in humans. — J. Appl. Physiol., 1986, 61, 932-939. 36. Freund, H., Oyono-Engulle, S., Heitz, A., Marbach, J., Ott, S., Gartner, M. Effect of exercise duration on lactate kinetics after short muscular exercise. — Eur. J. Appl. Physiol., 1989, 58,534-542. 37. Freund, H., Oyone-Engulle, S., Heitz, A., Ott, S., Marbach, J., Gartner, M., Pape, A. Comparative lactate kinetics after short and prolonged sub- maximal exercise. — Int. J. Sports Med., 1990,11, 284-288. 38. Fräser, R. S., Chapman, C. D. Studies on the effect of exercise on cardio­ vascular function. II The blood pressure and pulse rate. — Circulation, 1954, 9,193-198. 39. Foilenius, M., Brandenburger, G. Influence de l'exercice musculaire sur revolution de la cortisolemie et de la glycemie chez 1'homme. — Eur. J. Appl. Physiol., 1974, 33,23-33. 40. Fujitšuka, N., Yamamoto, Т., Õhkuva, Т., Saito, M., Miyamura, M. Peak blood lactate after short periods of maximal treadmill running. — Eur. J. Appl. Physiol., 1982, 48, 289-296. 41. Gellhorn, E. Autonomic imbalance and the hypothalamus. Minneapolis: The Univ. of Minnesota Press, 1957. 42. Gladden, L. В., Stainsby, W. N., Macintosh, B. R. Norepinephrine in­ creases canine skeletal muscle Vq2 during recovery. — Med. Sei. Sports Exerc., 1982,14,471^76. 43. Gollnick, E D., Bayly, W. M., Hodgson, D. R. Exercise intensity, training, diet, and lactate concentration in muscle and blood. — Med. Sei. Sports. Exerc., 1986,18,334-342. 44. Hagberg, J. M., Hickson, R. C., McLane, J. A., Ehsani, A. A., Winder, W. W Disappearance of nonepinephrine from the circulation following strenuous exercise. — J. Appl. Physiol., 1979, 47,1311-1314. 45. Hansson, E., Viru, A., Sildmäe, H. Vereringe näitajate muutused kii- ruslike ja kiiruslik-vastupidavuslike pingutuste puhul. — Eesti NSV IV Vabariiklik Teaduslik-metoodiline Konverents Kehakultuuri alal. Tallinn, 1961, 46-54. 46. Harris, P. Lactic acid and the phlogiston debt. — Cardiovasc. Res., 1969, 3,381-390. 95 47. Hatta, H., Atomi, Y, Yamamoto Y, Shinohara, S., Yamada, S. Oxidation of lactate in rats after short-term strenuous exercise. — Int. J. Sports Med., 1988,9,429-433. 48. Heniy, F. M., DeMoor, J. Metabolic efficiency of exercise in relation to work load at constant speed. — J. Appl. Physiol., 1950,2,481-487. 49. Henry, F. M., DeMoor, J. Lactic and alactic oxygen consumption in mod­ erate exercise of graded intensity. — J. Appl. Physiol., 1956, 8,608-614. 50. Hermansen, L., Osnes, J. B. Blood and muscle pH after maximal exercise in man. — J. Appl. Physiol., 1972, 32,304-308. 51. Hermansen, L., Stensvold, I. Production and removal of lactate during exercise in man. —Acta Physiol. Scand., 1972, 86,191-201. 52. Hermansen, L., Vaage, О. Lactate disappearance and glycogen synthesis in human muscle after maximal exercise. — Am. J. Physiol., 1977, 233, E422-E429. 53. Hermansen, L., Grandmontagne, M., Maehlum, S., Ingnes, I. Postexercise elevation of resting oxygen uptake: possible mechanisms and physiological significance. — Physiological chemistry of training and de­ training. Eds. P. Marconnet, J. Poortmans, L. Hermansen. Basel: Karger, 1984,119-129. 54. Hill, A. V. Muscular movement in man: The factors govering speed and recovery from fatigue. New York: McGraw Hill Book Co, 1927. 55. Holmgren, A. Circulatory changes during muscular work in man with special reference to arterial and central venous pressures in the systematic circulation. — Scand. J. Clin. Lab. Invest., 1956,8, suppl 24. 56. Häkkinen, К,, Pakarinen, A., Alen, M., Kauhanen, H., Komi, R V. Neuromuscular and hormonal response in elite athletes to two succes­ sive strength training session in one day. — Eur. J. Appl. Physiol., 1988, 57,133-139. 57. Isaev, G. G. Electromyographic analysis of breathing control during mus­ cular exercise. — Fiziol chel. (Moscow), 1986,12,219-228. 58. Jaružnyi, N. Y Dynamics of oxygen uptake in recovery period after short- term exercises of the highest power output. — Fiziol. chel., 1984, 10, 1042-1044 (in Russian). 59. Jensen, J., Oftebro, H., Breigan, В., Johnsson, A., Öhlin, К., Meen, H. D., Stromme, S. В., Dahl, H. A. Comparison of changes in testosterone con­ centrations after strength and endurance exercise in well trained men. — Eur. J. Appl. Physiol., 1991,63,467-471. 60. Jervell O. Investigation of the concentration of lactic acid in blood and urine. — Acta Med. Scand., 1928, suppl. 24. 61. Ježovä, D., Vigaš, M., Tatar, E, Kvetšansky, R., Nazar, K., Kaciuba- Ušcilko, H., Kozlowski, S. Plasma testosterone and catecholamine re­ sponses to physical exercise of different intensities in men. — Eur. J. Appl. Physiol., 1985, 54, 62-66. 62. Jorfeldt, L. Metabolism of (L+)-lactate in human skeletal muscle during exercise. — Acta Physiol. Scand., 1970, suppl. 138. 63. Juel, C., Bangsbo, J., Graham, Т., Saltin, B. Lactate and potassium flux­ es from human skeletal muscle during and after intense, dynamic knee extensor exercise. — Acta Physiol. Scand., 1990,140,147-159. 64. Karpman, V. L. Phasic analysis of cardiac acitivity. Moscow: Medicina, 1965 (in Russian). 96 65. Keizer, HL, Janssen, G. M. F., Menheer, P., Kranenburg, G. Changes in basal plasma testosterone, Cortisol, and dehydroepiandosterone sulfate in previously untrained males and females preparing for a marathon. — Int. J. Sports Med., 1989,10, suppl. 3, S139-S149. 66. Keul, J., Köhler, В., von Glutz, G., Berg, A., Howald, A. Biochemical changes in a 100 km run: carbohydrates, lipids, and hormones in serum. — Eur. J. Appl. Physiol., 1981,47,181-189. 67. Kindermann, W., Keul, J. Anaerobe Energiebereitstellung im Hoch­ leistungssport. Schörendorf: Hoffmann, 1977. 68. Kniittgen, H, G., Saltin, В. Muscle metabolism and oxygen uptake in short-term submaximal exercise in man. — J. Appl. Physiol., 1972, 32, 690-694. 69. Kocegub, Т. E, Feldkoren, В. I. Effect of exercise on the level of testos­ terone in blood of trained albino rats. —Acta Comment. Univ. Tartuensis, 1990,543,138-147. 70. Konovalova, G. M., Viru, A. A., Masso, R. A., Riuhhina, O. F. Changes of the concentration of thyroid hormones in the blood of rats after single bout of intensive exercise of short duration. — Hormonal regulation of adaptation of muscular activity. Tartu, 1991. 71. Krisanda, J. M., Moreland, T. S., Kushmerick, M. J. ATP supply and demand during exercise. — Execise, nutrition and energy metabolism. Eds. E. S. Horton, R. J. Teijung. New York: Macmillan Publ. Co, 1988, 27-44. 72. Kuoppasalmi, K., Näveri, H., Härkönen, M., Adlercreutz, H. Plasma Cor­ tisol, androstenedione, testosterone and luteinizing hormone in running exercise of different intensities. — Scand. J. Clin. Lab. Invest., 1980, 40, 403-409. 73. Kushmerick, M. G., Meyer, R. A. Chemical changes in rat leg muscle by phosphorus nuclear magnetic resonance. — Am. J. Physiol., 1985, 249, C362-C365. 74. Lindhard, J. Circulation after cessation of work, with some remarks on the calculation of circulatory rate experiments according the nitrous oxide methods. — J. Physiol., 1923, 57,17-30. 75. Lindhard, J. Untersuchungen über statische Muskelarbeit. I, II. — Skand. Arch. Physiol., 1920,40,145-210. 76. Maehlum, S., Grandmontagne, M., Newsholme, E. A., Sejersted, О. M. Magnitude and duration of excess postexercise oxygen consumption in healthy young subjects. — Metabolism, 1986,35,425-429. 77. Margomroth, M. L., Young, E. W., Sparks, H. V. Prostaglandin and his- taminergic mediation of prolonged vasodilatation after exercise. — Am. J. Physiol., 1977, 233, H27-H33. 78. Maron, M. В., Horvath, S. M., Wilkerson, J. E. Blood biochemical al­ terations during recovery from competitive marathon running. — Eur. J. Appl. Physiol., 1977, 36, 231-238. 79. Mateef, D. Ortostatische Kreislaufkollaps-Gravitations-shok (gravity shock). — Arbeitsphysiol., 1935, 8, 595-606. 80. McLennan, Т. M., Skinner, J. S. Blood lactate removal during active recovery related to the aerobic threshold. — Int. J. Sports Med., 1982, 3, 224-229. 13 97 81. Newman, E. V., Dill, D. В., Edwards, H. Т., Webster, E A. The rate of lactic acid removal in exercise. — Am. J. Physiol., 1937,118,457-462. 82. Pereni, R, Orizio, C., Comande A., Castellano, M., Berchi, M., Veiesteinas, A. Plasma norepinephrine and heart rate dynamics during recovery from submaximal exercise in man. — Eur. J. Appl. Physiol., 1989,58, 879-883. 83. Pruett, E. D. R. Insulin and exercise in non-diabetic and diabetic man. — Exercise endocrinology. Eds. K. Fotherby, S. B. Pal. New York: Gruyter, 1985,1-23. 84. Ratsimamanga, R. Variations de la teneur en acide ascorbique dans la surrenäle au cours du travail. — CR Soc. Biol., 1939,131, 863-865. 85. Rennie, M. J., Johnson, R H. Alteration of metabolic and hormonal responses to exercise by physical training. — Eur. J. Appl. Physiol., 1974, 33, 215-216. 86. Sagnol, M., Claustre, J., Cottet-Emard, J. M., Pequignot, J. M., Fellmann, N., Coudert, J., Pevyin, L. Plasma free and sulphated catecholamines after ultra-long exercise and recovery.—Eur. J. Appl. Physiol., 1990,60,91-97. 87. Sahlin, K., Harris, R. C., Nylind, В., Hultman, E. Lactate content and pH in muscle samples obtained after dynamic exercises. — Pflügers Arch, ges. Physiol., 1976, 367,143-149. 88. Sahlin, K., Avestrand, A., Brandt, R., Hultman, E. Intracellular pH and bicarbonate concentration in human muscle during recovery after exer­ cise. — J. Appl. Physiol., 1978, 45,474—480. 89. Sander, M., Röcker, L. Influence of marathon running on thyroid hor­ mone. — Int. J. Sports Med., 1988, 9,123-126. 90. Sildmäe, H. Die Änderung der Herzfrequenz bei Schiläuferinnen auf Grund telemetrische Messungen. — Acta Comment. Univ. Tartuensis, 1964,154, 21-29. 91. Somers, V. K., Conway, J., LeWinter, M., Sleight, R The role of baroreflex sensitivity in post-exercise hypotension. — J. Hypertens., 1985,3 (suppi.), S129-S130. 92. Sutton, J. R, Young, J. D., Lazarus, L., Hickie, J. В., Maksvytis, J. The hormone response to physical exercise. — Aust r. Ann. Med., 1969, 18, 84-90. 93. Sutton, J., Lazarus, L. Effect of adrenergic blocking agents on growth hormone response to physical exercise. — Horm. Metab. Res., 1974, 6, 428-429. 94. Svorovskaya, N. G. Transitory regimes of cardiac activity in alterations of venous return and muscular exercise in sportsmen. Theses of acad. dissert Tartu, 1990 (in Russian). 95. Tschaikovsky, V. S., Jevtinova, I. V., Basharina, О. B. Action of physical exercise on steroid content and reception of androgen in skeletal muscles. — Acta Comment. Univ. Tartuensis, 1985,702,105-114. 96. Vanhelder, W. R, Radomski, M. W., Goode, R. C. Growth hormone re­ sponses during intermittent weight lifting exercises in men. — Eur. J. Appl. Physiol., 1984, 53,31-34. 97. Vanhelder, W. R, Goode, R. C., Radomski, R. C. Effect of anaerobic and aerobic exercise of equal duration and work expenditure on plas­ ma growth hormone levels. — Eur. J. Appl. Physiol., 1984, 52,255-257. 98 98. Vanhelder, W. E, Goode, R. C., Radomski, R. C., Casey, К. Hormonal and metabolic response to three types of exercise of equal duration and external work output. — Eur. J. Appl. Physiol., 1985,54,337-342. 99. Viru, A., Oja, S., Viru, E. Changes in heart rate and blood pressure in weight-lifting. — Acta Comment. Univ. Tartuensis, 1968,205,74-81. 100. Viru, A., Kõrge, P. Study of adrenocortisol function in training pro­ cess. — Metabolism and biomechanical assessment of the fitness of sportsmen. Ed. N. Yakovlev. Leningrad: Leningrad Research Institute of Physical Culture, 1974,160-168 (in Russian). 101. Viru, A., Smirnova, Т., Tomson, К., Matsin, Т. Dynamics of blood levels of pituitary throphic hormones during prolonged exercise. — Biochem­ istry of exercise IVB. Baltimore: University Park Press, 1981,100-106. 102. Viru, A., Karelson, K., Smirnova, Т. Stability and variability in hormonal responses to prolonged exercise. — Int. J. Sports Med., 1992,13, 230- 234. 103. Viru, E. Dynamics of blood pressure during and after exercises of dif­ ferent intensity. — Acta Comment. Univ. Tartuensis, 1968, 205, 62-73. 104. Viru, E. The influence of body position on dynamics of blood pressure and heart rate after work. — Acta Comment. Univ. Tartuensis, 1968, 205, 54-61. 105. Volkov, N. I. Human bioenergetics in strenuous muscular activity and pathways for improved performance capacity in sportsmen. Moscow: Anokhin's Institute of Normal Physiology, 1990. 106. Vuori, L, Mariniemi, J., Rahkila, P., Vainikka, M. Plasma catecholamine concentrations and their responses to short-term physical exercise dur­ ing and after a six-day skihike. — Biochemistry of exercise IVB. Eds. J. Poortmans, G. Niset. Baltimore: Univ. Park Press, 1981,107-114. 107. Wasserman, K., Beaver, W. L., Davis, J. L., Pu Jum-Zang, Heber, R., Whipp, B. J. Lactate, pyruvate and lactate-to-pyruvate ratio during ex­ ercise and recovery. — J. Appl. Physiol., 1985,59, 935-940. 108. Weiss, M., Jockers, M., Barwich, D., Weicker, H. Das Stoffwechsel­ verhalten, seine hormonelle Regulation auf der kurzen und langen Wett­ kampfstrecke in Schwimmen. — Schweiz. Z. Sportmed., 1984,33,5-12. 109. Welch, H. G., Stainsby, W. W. Oxygen debt in contracting dog skeletal muscle in situ. — Resp. Physiol., 1967, 3, 229-242. 110. Weltman, A., Stamford, В. A., Fulco, С. Recovery from maximal effort of exercise: lactate disappearance and Subsequent performance. — J. Appl. Physiol., 1979, 47, 677-682. 111. Wirth, A., Diehm, C., Mayer, H., Mörl, H., Vogel, I., Björnstrop, P., Schlierg, G. Plasma C-peptide and insulin in trained and untrained subjects. — J. Appl. Physiol., 1981, 50, 71-77. 112. Zimkin, N. V., Razumov, S. A. Characteristics of changes of cardiac cycle durations in muscular exercise. — Physiological mechanisms of motor and autonomic functions. Eds. B. S. Hipperreiter, N. V. Zimkin, A V Korobkov, V. S. Farfel. Moscow: FiS, 1965, 94-102 (in Russian). 13* 99 STUDIES ON INTERRELATION BETWEEN BLOOD LACTATE AND UREA RESPONSES L. Litvinova, A. Viru Institute of Exercise Biology, University of Tartu, 18. Ülikooli Street, Tartu, EE2400 Estonia Abstract In order to test the relation between urea and lactate respons­ es to exercise, the dynamics of these metabolites and glucose were studied in skiing on rollers for 40 km (11 adult biathlonists), biathlon on rollers for 21 km or in running for 26 km (10 junior biathlonists) and in ice-hockey training session (10 adult hockey players). 40 km skiing on rollers, biathlons for 21 km on rollers or for 26 km in running caused a gradual increase of urea level. Blood lactate levels elevated up to the level considered to indi­ cate the anaerobic threshold (4 mmol •1 _1). In ice-hockey players the main part of the exercise session increased urea concentration. The lactate level elevated up to 4,33 ± 0.27 mmol • I-1. When the test for anaerobic working capacity followed, the lactate concentra­ tion rose up to 14.1 ± 0.49 mmol • 1 , but urea dropped to initial values. No significant change was found in blood glucose level. The obtained results indicate that the reciprocal relation between lactate and urea responses to exercise appears when blood lactate concentration increases for above the level of anaerobic threshold. Key words: exercise, glucose, lactate, urea. Introduction A great body of results evidence the exercise-induced increase in urea production, reflected in elevated urea levels in blood and tissues (for reviews see [5, 6, 8, 10, 11]). However, it has been reported that the optimal activity of several enzymes catalyzing biochemical reactions concerned in urea synthesis is at pH 7.7. At pH 7.1 urea synthesis was reduced by 40% in the liver [5, 9]. In order to test the contribution of lactate in control of urea synthesis, the urea and lactate dynamics were plotted in athletes during various prolonged exercises. 100 Methods Subjects An informed consent was obtained from highly qualified athletes. The persons constituted groups of 11 adult biathlonists (age 18- 26 years), 10 junior biathlonists (age 16-18 years) and 10 ice-hockey players (age 18-27 years). All sportsmen were under systematical medical control. According to their health conditions they were al­ lowed for training with high loads and for participation in competi­ tions. Protocol (1) 40 km of skiing on rollers performed by 12 adult biathlonists in June: blood sampling in the morning and after 10, 20, 30 and 40 km was passed; (2) The same exercise was repeated a month later on the same sportsmen; (3) 26 km of biathlon in running performed by 12junior biathlonists in July; blood sampling in the morning and after 12 and 26 km was passed; (4) 21 km of biathlon on rollers performed by 12 junior biathlonists in July; blood sampling in the morning and after 10.5 and 21 km was passed; (5) training session consisting of 20-min warm up, 45 min training game of ice-hockey and then a specific test of anaerobic working capacity (6 x 45 m dribbling at the highest rate); blood sampling in the morning, after training game, the test for anaerobic working capacity, and 30 min recovery after the end of session. Blood samples were taken from the fingertip after a short-term heating. The first sampling was performed in the morning before breakfast. The next samples were obtained during exercise at various time points (see above). The exercise session began 2 h after the breakfast (10 a.m.). Before the studied exercises, usual warm-up was performed by the sportsmen. Analyses Urea, lactate and glucose were measured by standard procedures using commercial kits of lachema Bio-La-Test (Czech Republic). All analyses were made immediately after sampling in duplicate. The differences between duplicates did not exceed 8%. Exercise-induced changes were statistically evaluated using paired t-test. Individual results obtained during exercises at various time 101 points were compared to the initial level in the same person. Proba­ bility of 0.05 was designated as significant. Results The skiing on rollers for 40 km resulted in a gradual increase of urea concentration (Fig. 1). The lactate concentration rose during first 30 km and levelled off on average values (± SE) of 4.09 ± 0.48 mmol • l-1 (after 40 km). The blood glucose level re­ mained constant throughout the exercise. The skiing velocity in­ creased during the first 20 km and decreased during the last 10 km. Individual analysis revealed two extreme variants (Fig. 2). One of them was characterized by a moderate decrease of skiing velocity in association with further increase of blood lactate from the 30th to 40th km up to the value 6.3 mmol • I-1. In this case urea concentration decreased during the last 10 km. In the other variant a pronounced drop in skiing velocity occurred during the last 10 km in association with reduction of lactate level (4.4 mmol • l-1 after the end of exercise) and further elevation of urea level. mmol-1 1 10.0- m-i ,-l 8.0 Urea Velocity • 5.34 5.26 Glucose - 5.18 -A - 4.0 . Lactate 2.0 1. ± X x Before 20 40 km Fig. 1. Dynamics of blood metabolites during 40-min skiing on rollers. Open triangles — urea (mmol-1-1), crosses - skiing velocity (m-s-1), closed triangles—glucose (mmol •1 —1), closed small circles—lactate (mmol-1-1). 102 m-s- 1 -5.8 Veolocity Urea - 6 . 0 -5.6 4.0 5.4 Lactate - 2.0 - 5.2 Before 10 20 30 40 km mmol-1 1 m-s- 1 Urea •9.0 Velocity . 5.8 5.6 •5.0 Lactate 5.4 3.0 5.2 1.0 Before 10 20 30 40 km Fig. 2. Two individual cases of dynamics of blood metabolites during 40-min skiing on rollers. Open triangles — urea (mmol-1 *), crosses — skiing velocity (m • s~*), closed small circles — lactate (mmol -1 1). 103 In repetition of the same exercise a month later no principal dif­ ferences in results were found except of a mild initial hyperglycemia (Table 1). T a b l e 1 Changes in urea, lactate and glucose levels (mmol • I-1) in adult biathlonists during 40 km skiing or rollers in July (mean ± SE) Time of n Average Urea Lactate Glucose sampling velocity m • s Before 11 6.58 ± 0.23 1.81 ± 0.12 5.11 ± 0.17 After 10 km 11 5.34 ± 0.09 7.11 ± 0.31 3.50 ± 0.15* 5.18 ± 0.21* 20 km 11 5.34 ± 0.09 8.00 ± 0.34* 3.75 ± 0.15* 5.20 ± 0.16 30 km 11 5.29 ± 0.10 8.50 ± 0.42* 3.93 ± 0.19* 4.93 ± 0.14 40 km 11 5.53 ± 0.08 9.07 ± 0.30* 4.36 ± 0.24* 5.00 ± 0.25 Asterisk denotes significant difference (P < 0.05) from the initial values. In junior biathlonists control training performed in summer on rollers or in running caused a gradual increase of both urea and lactate levels (Table 2). However, the lactate concentration increased only up to 4.54 ± 0.29 mmol • l-1 after the training session on rollers or up to 4.00 ± 0.29 mmol •1 _1 after the running training session. T a b l e 2 Changes in urea and lactate levels (mmol • l-1) in junior biathlonists during control training sessions in running or in skiing on rollers (mean ± SE) Time of n Average Urea Lactate sampling velocity m s - 1 RUNNING Before 10 5.00 ± 0.26 1.37 ± 0.07 After 13 km 10 3.88 ± 0.06 7.75 ± 0.24* 3.00 ± 0.20* After 26 km 10 3.34 ± 0.11 9.02 ± 0.38* 4.00 ± 0.29* SKIING ON ROLLERS Before 10 5.58 ± 0.19 1.67 ± 0.09 After 10.5 km 10 4.11 ±0.11 6.20 ± 0.15* 4.57 ± 0.22* After 21 km 10 4.53 ± 0.06 6.94 ± 0.23* 4.54 ± 0.29* Asterisk denotes significant difference (P < 0.05) from the initial values. In ice-hockey players the main part of the training session in­ creased significantly level of urea (Fig. 3). Lactate level elevated 104 up to 4.33 ± 0.27 mmol-1-1. When the test for anaerobic work­ ing capacity was performed, the lactate concentration rose up to 14.14 ± 0.49 mmol • l-1, but urea dropped to initial values. 30 min after session both urea and lactate concentration were close to the initial level. No significant changes in blood glucose were found. mmol-1 Lactate Urea 12.0 6.0 8.0 4.0 4.0 2.0 Before After After test the main 30 min after of anaerobic part capacity Fig. 3. Dynamics of blood metabolites during a training session in ice-hockey. Open triangles — urea (mmol • l-1), closed small circles — lactate (mmol-1-1). Discussion The obtained results indicate that the reciprocal relations between blood lactate and urea responses appear only when the lactate con­ centration rises far over the level of anaerobic threshold. This level is considered to be 4 mmol • l-1 [3]. Our results are in accordance with the following facts: (1) the urea response appears mainly in aerobic exercise and de­ pends on exercise duration [2,7, 8]; (2) when short-term intense exercise is considered, blood urea remains relatively stable [1, 7,8]; (3) in sportsmen the usual dependence of blood urea increase on the training load disappeared when highly intensive exercises were included into the sessions [11]; (4) at pH 7.1 urea synthesis was reduced by 40% in the liver [5, 9]. 14 105 The first possibility to explain the inverse relationship between high lactate levels and urea concentrations is the inhibition of enzymes concerned in urea synthesis by pH decrease. However, in ice-hockey players the drop in urea concentration appeared to be rapid when an anaerobic exercise was performed. Obviously the inhibition of the urea synthesis had to be in combination with elevated urea elimination from the blood. A general effect is the increased renal clearance of urea, appearing after prolonged exercise [4]. By results of Gorski et al­ ii] in response to vigorous anaerobic exercise (blood lactate rose up to 15 to 17 mmol • I-1) blood urea did not change and urea excretion by urine decreased. However, urea excretion by sweat increased. The latter is an opportunity to explain the rapid urea elimination from the blood during anaerobic exercises. REFERENCES 1. Görski, J., Lerczak, K., Wojcieszak, J. Urea excretion in sweat during short-term efforts of high intensity. — Eur. J. Appl. Physiol., 1985, 54, 416-419. 2. Haralambie, G., Berg, A. Serum urea and amino nitrogen changes with exercise duration. — Eur. J. Appl. Physiol., 1976,36,39-48. 3. Heck, H., Madar, A., Hess, G., Muncke, S., Müller, R., Hollmann, W. Justification of the 4 mmol/1 lactate threshold. — Int. J. Sport Med., 1985, 6,117-130. 4. Litvinova, L., Viru, A., Smirnova, Т. Renal urea clearance in normal and adrenalectomized rats after exercise.—Jpn. J.P hysiol., 1989,39,713-723. 5. Lorenz, R., Gerber, G. Harnstoff bei körperlichen Belastungen: Verän­ derungen der Synthese, der Blutkonzentration und der Ausscheidung. — Med. u. Sport., 1979,19, 240-248. 6. Neuman, G. Metabole Regulation bei Langzeitausdauerleistungen. — Med. u. Sport., 1983, 23,169-175. 7. Poortmans, J. R. Protein turnover and amino acid oxidation during and after exercise. — Med. Sei. Sport., 1984,17,130-147. 8. Poortmans, J. R. Protein metabolism. — Principles of Exercise Biochem­ istry. Ed. J. R. Poortmans. Basel: Karger, 1988,164-193. 9. Saheki, Т., Katunuma, N. Analysis of regulatory factors for urea syn­ thesis by isolated perfused rat liver. I Urea synthesis with ammonia and glutamine as nitrogen sources. — J. Biochem (Tokyo), 1975, 77, 659-669. 10. Viru, A. Mobilization of structural proteins during exercise. — Sports Med., 1987,4, 95-128. 11. Voznesensky, L. S., Zaleskij, M. Z., Arzhanova, G. D., Tõshkevitch, V. V. Control of blood urea in cyclic sports events. — Teoria i prakt. fiz. kult., 1979,10,21-23. 12. Zerbes, H., Kühne, К. Götte, H.-C. Der Einfluss von Körperlicher Be­ lastung und Eiweßgehalt der Nahrung auf die Harnstoffproduction, - exkreation und -retention. — Med. u. Sport, 1983, 23, 299-301. 106 FLEISCH PULSZEITSCHREIBER: AN EFFECTIVE METHODOLOGICAL PRINCIPLE. SIGNIFICANCE FOR EXERCISE PHYSIOLOGY A. Viru Institute of Exercise Biology, University of Tartu, 18. Ülikooli Street, Tartu, EE2400 Estonia Abstract The "Pulszeitschreiber", constructed by A. Fleisch in 1930, was designed for recording of the time intervals between arterial pulses. The obtained recordings of the cardiac cycle provided good oppor­ tunities for analyses of the cardiac rhythm. The use of the record­ ings of R peak of ECG instead of arterial pulses as the impulse discriminating cardiac cycles, widened essentially the opportuni­ ties to use this method. An teleintervaliograph was constructed for using the method in athletes in normal training conditions. Later on the basis or prolonged registration, methods were elaborated for computerized analysis of the cardiac rhythm. The diagnostic and prognostic values of this approach in operative control of the organism's state was confirmed in various physiological and clinical conditions, including studies on athletes. The Fleisch method sup­ plied exercise physiology also with data on the transition process at the beginning and after the end of exercise, as well as cardiac rhythm in the anticipatory state, during exercise, and in postexer- cise recovery. Introduction Similarly to every man or woman, each apparatus has is own fate. There are apparatuses of short life-span. There are apparatuses pos­ sessing long-lasting life. There are also apparatuses which remain alive longer than their own life-span. Those are apparatuses which provide a new methodological approach or a new methodological principle. The Pulsezeitschreiber constructed by A. Heisch belongs to the last group. ТЪе Pulszeitschreiber was aimed for continuous recording of the 14* 107 heart rate. Before Fleisch there were some attempts to find possibil­ ities for continuous recording of the heart rate. However, they were too complicated and did not provide a comprehensive picture. The complications were overcome by A. Fleisch, using a new and simple but fruitful idea: record the duration of each cardiac cycle — the 'Pul- szeit'. It meant the continuous registration of time intervals between subsequent contractions of the myocardium. The idea of A. Fleisch A. Fleisch published the principle and description of the appara­ tus in 1930 [3] (Fig. 1). The new idea lay in recording of the time intervals between arterial pulses by drawing vertical lines, the height of which each corresponded to the time of a cardiac cycle (Fig. 2). This approach provided the visualization of subtle alterations in car­ diac rhythm. Tbus a principle of visualization of the studied process was used. It is not necessary to emphasise the essential role of the principle in the methodology of physiological studies. In the Pulszeitschreiber, the principle was used in the following manner. The writing device of the apparatus draws vertical lines on the kymograph tape. An impulse from the device receiving the arterial pulsation, breaks off the upward movement of the writer and with the help of a spring, the writen quickly falls down to the basal line. Immediately after, a new upward movement of the writer begins (Fig. 3). In this way the height of each vertical line corresponds to the time of subsequent cycle. The arterial pulses were transferred to electrical impulses with the aid a special pelot (Fig. 3). Each pulse caused an increase of the mercury in a capillar tube up to an electrode. Since the electrode and the mercury tank were connected with a source of electrical current, the electrical chain closed. In result an impulse was created breaking off the upwards movement of the Writer. Somewhat later the apparatus was adjusted for recording of time intervals in various physiological experiments. For example, M. Tiitso adjusted it for registration of cardiac rhythm in animal experiments [25]. The apparatus was adjusted for recording of time intervals be­ tween the formation of subsequent drops of fluid. It gave a possibility to use the apparatus in studies of the action of vasoactive substances on the blood flow rate in rabbit ear preparation. The recording of time intervals between drops was useful also in studies of the digestive pro­ cess. The Pulszeitschreiber was used also for continuous registration of pedaling cycle time in exercising on bicycle ergometer [37]. A new variant of the apparatus was described by A. Fleisch in 1954 108 ZEITSCHRIFT FÜR DIE GESAMTE EXPERIMENTELLE MEDIZIN züoustort mrstitzuftö bim ZEITSCHRIFT FÜlt RXVISUIMBNTRl.l.E l'ATHOLOOlfi tNt) 1НЕПАИЕ ШАШВШОШШ VOH B. ABllKttilAi,tlES.HALL8, tl. h 1МвИШ4Й&Ш, A. «lRfiL-ftUa, TU. URVOiClt-MALliB A, 8., 8. KB"»*" t ' lt. ЁРИЯв«. fBEiiiuttd t вв., и. t, илейкйй-вшшкш, it, й. HeftiMd-Köut, W. IHS-BBitLtN, F. KBAtll-BRttLUS, МШМСЙ-ВВЙШ, 6, t. NoOKbBR. wtiCH, fi.PAtR.l,ElPZ10, тП1Л1А1ШВСМШ1>0ВВК,K SAÜBBhttUcn. BERUH, А. вШтшИШ-МЛЬ, IL STRADB.tifrJrmtOßtit, W. iTttAütt- liüNOH«N,VT.TRBI1ÖBL6il»6sSeÖ@StUt,RtmLef1ltt)Tll.pREtBöRa t.BR., r. tdUIAttb-iftAKltirtiRf А. M. BRoiattiBf vos F. К It AUS С. PmqtJET t Ä, SClllTf ßNBELM W. TRENDELENBURG Sondtrdrvck Ш Hand 79, Я. w, 4, Heß. Alfred flellefl! Der PitlužcttBclirelbei1; feilt AiHfrtMt žtif Außsetetüiutig del« zeHlloheit PttlsiittfemUö ftle Ordinate, B K l t f i l N v ß t i L A d V O M » ö t A ü s е^тноЁй 108Õ Fig. 1. The title page of the Fleisch publication on the Pulszeitschreiber 109 /Уллл^^^^Длллл ̂ l.o -I ! 1.8 - о • I ', i \ \ \ \ \ \ ; 1 М '• ' ' • » '• ' ' Fig. 2. Examples of recording the duration of cardiac cycles by the Fleisch principle. The dynamics of cardiac activity during a voluntary stop of breathing. From the top: (1) pneumogram, (2) duration of cardiac cycles, (3) time per 3 sec. The figure is obtained from the author's archives. [6]. The principle of recording of cardiac cycle duration or other time intervals by means of vertical lines has been used by several researches [13]. Registration of the cardiac rhythm Continuous recording or the cardiac cycle provided good oppor­ tunities for analysis of the cardiac rhythm [4, 25, 40]. In addition to the respiratory arhythmia, waves in the duration of cardiac cycle with periods from 8 to 16 s were described ("Langwellen"). Likely, these waves correspond to the tertial waves in arterial blood pressure. As early as 1932 it was suggested that pronounced respiratory arhyth- 110 кЖ BOS /~Л Fig. 3. The Fleisch Pulszeitschreiber. On the upper panel: the principal scheme. On the lower panel the pelot for receiving arterial pulses. All Figures are from the original publication of A. Fleisch. Ill mics is typical for the young heart possessing a good working capacity [40]. Later ontogenetic pecularities were discovered in the respiratory arhythmics: at the age of 10 to 15 years the respiratory arhythmics was characterized by a great diapasone between the shortest and longest cardiac cycles. In this age the so called "Vagus pulse" (Fig. 4) — single long cardiac cycles (up to twice longer as the mean level) — may appear on the second half of expiration [8]. These long cardiac cycles did not differ from others by the ECG; children who exhibited the vaguspulse had normal physical capacities [27]. The method has been used also for studying the dynamics of cardiac responses to various actions, including psychic strain [5], vagotomy, administration of atropine or adrenaline, Ashner reflex, and Valsalva maneuver [2,4,15-17,21,25,40]. The further development of the method consisted in substitution of arterial pulses by R peak of ECG as the impulse discriminating cardiac cycles [20] (Fig. 5). A teleintervallograph was constructed for continuous recording of the action of exercises in athletes in normal conditions of sports activities [14]. The principle for time interval recording, including cardiac cycles, was used in various multichannel monitor-physiographs, constructed in the Laboratory of Biophysics of the University of Tartu and elsewhere. Comparing the principle proposed by A. Fleisch for recording of cardiac cycle duration with the usual ECG studies, one must to point out not only the excellent visualization of the dynamics but also the good opportunities for prolonged registration. Later, on the basis of prolonged registration, methods were elaborated for computerized analysis of the cardiac rhythm. The diagnostic and prognostic val­ ue of this approach in operative control of the organism's state was confirmed in various physiological and clinical conditions, including space flights [1]. However, a great material collected by a Lithuanian group indicated that the value of such methodological approach es­ sentially increases if the computerized analysis of the cardiac rhythm is performed together with analyses of the cardiac dynamics recorded by the Fleisch principle [41]. Significance for exercise physiology The first attempt to use the Pulszeitschreiber in exercise studies was made by B. Wilhelmson [40]. She recorded cardiac activity dur­ ing exercises of mild intensity. The main result was the decrease of the respiratory arhythmies with increased heart rate. However the "Langewellen" persisted. In the next study more intense exercises performed on a bicycle ergometer were used [24]. There were cases 112 лЛШШШ, when heart rate increased up to 200-205 beats per min. The con­ tinuous registration of cardiac cycle duration enabled the authors an opportunity for exact description of the heart rate dynamic pattern during and after exercise. Also the heart rate increase was noticed after command preceding the exercise. During exercise the respirato­ ry arhythmies decreased with increase in heart rate until the absence of arhythmies. After exercise the arhythmies as well as "Langwellen" became pronounced. However, in untrained persons after very in­ tense exercise the heart rate recovery was slow. During the first two minutes or more the respiratory arhythmies was hardly visible. In 1950s the Fleisch method was used to demonstrate the effect of forced expiration on the heart rate recovery [28]. A special anal­ ysis was made on the short-term heart rate response to commands preceding exercise [29]. In the anticipatory state before sports com­ petitions two variants were found: (1) a pronounced increase in heart rate associated with reduced respiratory arhythmies, (2) a moderate increase in heart rate accompanied by a pronounced augmentation of respiratory arhythmies [30]. The exercise studied with the original method were complicated due to the fact that the arm fixed in the pelot for reception of arterial pulses had to be immovable. The complication was surpassed by substition of the arm pelot by ECG electrodes. In a great number of persons of both sexes and various fitness levels heart rate dynamics were recorded in very intense sprint of 15 s and in exercise lasting 3 min. The results of Tiitso and Pehap [24] were confirmed and extended [7]. A possibility of regulatory interia was shown that was reflected in further increase of heart rate during a few seconds after exercise, or the possibility that heart rate might persist for 5-10 s on the exercise level before its decrease. In trained persons the fast postexercise decrease in heart rate associated with the augmentation of respiratory arhythmia and "Langwellen". Further, a long chain connecting the person and the apparatus was used. This allowed researchers to record the heart rate during and after various sports exercises: swimming for 25 and 100 m [18 35], gymnastic exercises on the beam, arm bending [31, 35] or weight lifting [36] (Fig. 6). Postexercise recordings were made also in runners after they finished runs for 100 or 400 m [32]. In order to use the obtained results for information on the function­ al capacity of persons, the total number of heart beats during the first three postexercises minutes (sum of recovery pulses) was accounted and used in relation to the actual intensity of the performed exercise [31, 32, 35]. This approach was used in control of training efficiency in Estonian top athletes [9,18, 31]. The method of continuous regis­ tration of heart rate was used for analysis of fatigue development in repeated exercises or test exercises performed before and after train- 15* 115 f '' ' ' * 'f' 1 '' i •' 4 '' 'l • I ! 1 Г л;; ?< it i 4 Л M i^i i'* Д . I f f Fig. 6. Dynamics of duration of cardiac cycles in transition from rest to var­ ious exercises. From the top: (1) Transition to swimming for 100 m: first arrow indicates the command to take in the water the starting position, the second arrow — persons sunk into the water to take the starting position, the third arrow — the start. (2) Transition to weight lifting: the arrows indicate the command to go to the bar, and the onset of lifting. (3) Transition to and exercise on the gymnastic horse: the arrow indicates the command to go to horse, and the onset of exercise. Time is indicated per 5 sec. The figures were obtained from the author's academic dissertation for the degree of candidate of biological sciences. 116 ing sessions [19, 33, 34]. Experiments were performed also in order to compare the dynamics of heart rate and blood pressure during and after exercises of various duration and intensity [39] and to study the significance of body position for the recovery process [38]. Using the teleintervallograph in skiers, results were obtained demonstrating that in highly qualified skiers a good accordance exists between heart rate and the relief of the skiing track. In less qualified skiers the accordance was less pronounced. Skiers of low level failed to show the accordance. The results made possible also to evaluate the precondition for heart rate rise over 200 beats per min. This phe­ nomenon was found in skiers of medium qualification. It was never found in skiers of either high or low qualification. It was suggested that heart rate rises over 200 beats per min in sportsmen having a certain level of fitness of the muscular system in association with a poor development of cardiovascular fitness [22]. In a study durations of both cardiac cycle and pedalling revolution were monitored during cycling exercises of various intensity. It was found that when heart rate increased over1 60 beats per min, durations of the cardiac cycle remained constent despite variations in time of pedalling revolutions. Also the respiratory arhythmies disappeared [37]. More recently two extended studies were performed using the Heisch principle for recording of the heart rate pattern in exercis­ es. Results of A. Kepezhenas [11, 12] showed that in sportsmen the increase of aerobic working capacity associated with elevated respi­ ratory arhythmies on the level of pronounced bradycardia. However, a further increase of aerobic working capacity might reduce the res­ piratory arhythmia. Temporary drops in performance capacity were reflected by increased heart rate in rest and during functional tests and reduced respiratory arhythmies. Four variants of patterns of postexercise recovery of heart rate were described by N. Svoroskaya [23]. The appearance of these variants depended on the ratio between cardiovascular fitness and exercise intensity. In transition from rest to exercise an exponential increase or the phenomenon of search were found. The changes in the amplitude of respiratory arhythmies have been used for differential evaluation the significance of increased parasym­ pathetic tone or decreased sympathetic tone in origin of training bradycardia [10]. This study was also made by using the Fleisch prin­ ciple. A close relationship between aerobic power and vagal tone was indicated in control of resting heart rate. In conclusion, the Pulszeitschreiber was not only an apparatus for continuous registration of heart rate. By this apparatus a newprinciple was provided for continuous registration of physiological processes. In this way the method warranted an accumulation of valuable phys­ 117 iological information. The method promoted the development of exercise physiology. REFERENCES 1. Bajevsky, R. M. Prognostics of states on the breadline of norm and pathol­ ogy. Moscow: Medicina, 1979 (in Russian). 2. Epler, M. Okulokardiaalrefleks ja selle alusel kujundatavad tingitud seo­ sed inimesel. Dissertatsioon. Tartu, 1953. 3. Fleisch, A. Der Pulszeitschreiber; ein Apparat zur Aufweichung der Zeit­ lichen Pulsintervalle als Ordinate. — Zschr. ges. exper. Med., 1930, 72, 384-390. 4. Fleisch, A., Beckmann, R. Die raschen Schwankungen des Pulsfrequenz registriert mit dem Pulszeitschreiber. — Zschr. ges. exper. Med., 1932, 80,487-510. 5. Fleisch, A. Über das Verhalten der Pulsfrequenz bei seelischer Erregung, registriert mit einem neuen Zeitordinatenschreiber. — Arch. ges. Psyc­ hol., 1933, 87,534-540. 6. Fleisch, A. Eorthochronographe. — Nouvelles metodes d'etude des ec- hanges gaseux et de la fonction pulmonaire. Basel, 1954. 7. Hansson, E.,V iru, A., Sildmäe, H. Vereringe näitajate muutused kiiruslike ja kiiruslik-vastupidavuslike pingutuste puhul. — Eesti NSV IV vabari­ iklik teaduslik-metoodiline konverents kehakultuuri alal. Tallinn, 1991, 46-54. 8. Käer-Kingissepp, E. G., Epler, M. A. On ontogenetic pecularities of vari­ ability in duration of cardiac cycle. — Proceedings of the 3rd Scientific Conference in Ontogenetic Morphology, Physiology and Biochemistry. Moscow: Acad. Ped. Sei, 1959, 249-255 (in Russian). 9. Kalam, V., Viru, A. Results of the investigation of the training of the Es­ tonian national team in track and field before the 3rd People Spartakiade of the U.S.S.R. — Acta Comment Univ. Tartuensis, 1968,205, 99-105. 10. Kenney, W. L. Parasympathetic control of resting heart rate: relationship to aerobic power. — Med. Sei. Sports Exerc., 1985,17,451-455. 11. Kepezhenas, A., Zhemaityte, D. Dependence of structure of heart rhyth­ mics on physical working capacity of sportsmen. — Fiziol. chel., 1983, 9, 729-739 (in Russian). 12. Kepezhenas, A. Characteristics of heart rhythmics in adaptation to phys­ ical exercises. — Theses. Leningrad, Research Institute of Experimental Medicine, Acad. Med. Sei. U.S.S.R., 1984 (in Russian). 13. Khayutin, V. M. Intervalograph — an apparatus for registration of physi­ ological processes by a time-impulse method. — Byull. eksper. biol. med., 1955,40, 8, 72-75 (in Russian). 14. Kiis, H., Reeben, V., Sildmäe, H. Die Anwendung der Teleintervallograp- hen beim Registrieren der Herzfrequenz während sportlicher Arbeitsleis­ tung. — Acta Comment. Univ. Tartuensis, 1964,154,101-108. 15. Looga, R. Reflectory responses of cardiovascular system and respiration to increased intrapulmonary pressure in animals.—Acta Comment. Univ. Tartuensis, 1956,40, 3-16. 118 16. Looga, R. Reflectory changes of heart activity in usual and modified (Valsalva und Müller maneuvers) respiration. — Acta Comment Univ. Tartuensis, 1956,45,23-35. 17. Looga, R., Kull, M., Looga, L. On changes of arterial pressure and heart rhytmics after adrenaline administration in dogs. — Scchenov Physiol. J.U.S.S.R., 1965,51,564-571 (in Russian). 18. Oja, S-, Vlra, A,, Vire, E. Alterations of heart rate and arterial pressure during swimming for 100 meters at maximum and submaximum speeds. — Acta Comment Univ. Tartuensis, 1968,206,44-53. 19. Pisufee, A. Südametegevuse dünaamikast intervallmeetodi rakendamisel jooksjate treeningus. Acta Comment Univ. Tartuensis, 1968,205,82-98. 20. Reeben, V A., Unger, J. A. A cardiot achometer with interval registration. —Sechencw Physiol. J. USSR, 1960,46,356-360. 21. RHII, A. Respiratoorsest arütmiast vagotoonia puhul. Dissertatsioon. Tar­ tu, 1947. 22. Sildmäe, H. Die Änderung der Herzfrequenz bei Schiläuferinnen aus Grun Telemetrischer Messungen. — Acta Comment. Univ. Tartuensis, 1964,154,21-29. 23. Svorovskaya, N. G. Transitory regimes of cardiac activity in alterations of venous return and muscular exercise in sportsmen. Theses. Tartu, 1990 (in Russian). 24. Tiitso, M., Pfchap, A. Über den Einfluss der Körperarbeit auf die Pulsfrequenz. — Arbeitsphysiol., 1935, 9,51-61. 25. Tiitso, M., Tootsen, Е. Über die Ursache der respiratorischen Arryth- mie. — Pflügers Arch. ges. Physiol., 1935,236, 251-260. 26. Tiitso, M. Über die Methode der Registrierung von Pulsintervallen als Ordinate im Tierversuch. — Pflüger Arch. ges. Physiol. 1937, 239, 265- 273. 27. Unger, J., Viru, A. Ebaühtlase südamerütmi seosest laste kehalise võime­ kusega. — Nõukogude Eesti Tervishoid, 1963, 3,7-8. 28. Viru, A. Võimalusest kiirendada südametegevuse füüsilise töö järgset taastumist. — TRÜ toimetised, 1956,42,78-83. 29. Viru, A. On changes of heart rate in start to ergometer exercise. — Pro­ ceedings of Conference on Sports Physiology, Biochemistry and Mor­ phology. Moscow, 1959,154-158 (in Russian). 30. Viru, A. On changes in cardiac rhythmics before the start of a sport contest. — Acta Comment. Univ. Tartuensis. 1961,106, 61-73. 31. Viru, A., Oja, S., Sildmäe, H., Reintam, Õ., Viru, E. Eesti NSV koond­ võistkondade liikmete südame-veresoonte süsteemi funktsionaalsete või­ mete võrdlev analüüs. — Eesti NSV VI vabariiklik teaduslik-metoodiline konverents kehakultuuri alal. Tartu, 1963. 32. Viru, A., Nurmekivi, A., Omrauk, B. On the determination of fitness by means of functional tests. — Acta Comment. Univ. Tartuensis, 1964,154, 3-20. 33. Viru, A., Viru, E. De la participation des surrenals dans l'adaptation de l'organisme a la sortie d'un entrainement a grande charge. — Acta Comment. Univ. Tartuensis, 1964,154, 78-96. 119 34. Viru, A. On the development of discoordination between working capacity of the motor apparatus and organism's adaptivity in fatigue.—Physiolog­ ical Mechanisms of motor and autonomic function. [Eds. B. Hippenreiter, N. Zimkin, A Korobkov, V. Farfel.] Moscow: FiS, 1965,102-112 (in Rus­ sian). 35. Viru, A., Oja, S., Sildmäe,H ., Viru, E. On the correlation between changes of heart rate and arterial pressure during sport efforts and during one- minute runs on the spot. — Acta Comment. Univ. Tartuensis, 1968, 205, 33-43. 36. Viru, A., Oja, S., Viru, E. Changes in heart rate and blood pressure in weight-lifting. — Acta Comment. Univ. Tartuensis, 1968,205,74-81. 37. Viru, A. Interrelations between rhythms of working movements and heart rate. — Experimental and Clinical-physiological Studies on Motor- visceral Regulation, 1971,10,18-22. 38. Viru, E. The influence of body position on dynamics of blood pressure and heart rate after work. — Acta Comment. Univ. Tartuensis, 1968,205, 54-61. 39. Viru, E. Dynamics of blood pressure during and after exercises of different intensity. — Acta Comment. Univ. Tartuensis, 1968, 205, 62-73. 40. Wilhelmson, B. Die Schwankungen der Pulsfrequenz bei Belastung der Herzens. — Zeitschr. ges. exper. Med., 1932, 85,248-261. 41. Zhemaityte, D., Telksnis, L. Analysis of Cardiac Rhythm. Vilnius: Mok- slas, 1982 (in Russian). 120 SENSITIVE PERIODS OF PHYSICAL DEVELOPMENT J. Loko, T. Sikkut, R. Aule Institute of Coaching, University of Tartu, 18. Ülikooli Street, Tartu, EE2400, Estonia The coaches and teachers of physical education are well aware of the fact that the students cannot develop all the characteristics and abilities in the same way. The development of a person is determined by genetic and social programmes. The genetic factors determine the potential possibilities of the development. The process of passing on genetic information takes place at its best in certain external condi­ tions. When the certain genetic information is missing, the quality does not develop even if the optimum external conditions are provid­ ed. The possibilities of developing sporting abilities are not endless and are limited by the genotype of an individual [6, 7, 9,10,14,15]. It has been provided that the genetic information can be realised only if it is during every age period in optimum correlation with cer­ tain external environmental conditions and with the morphological and functional characteristics of certain age periods. The effective­ ness of sport developments is noticeably higher when pedagogical influence coincides with the individual anatomical and physiological peculiarities of every age group [3,4,8]. The factors of pedagogical influence must correspond to the bio­ logical rhythm of motorics in different age groups. The influence of environmental factors (sport training) is not the same at different levels of the development of the organism. During every period of the individual development a certain complex of exercises and methods, based on the earlier changes in the organism and genetic information, gives the biggest effect. External factors that do not correspond to the abilities of the organism do not enable us to use the reserves that the organism has at different levels of its development. Only close connection with external environment makes it possible to develop heredity. The exercises and methods should favour the development of the hereditary abilities of young sportsmen. Inadequate influence can result in only partial revelation of these abilities, whereas in case of excessive loads the genetic possibilities can be exhausted. It leads to the necessity for the choice of optimum training load [1, 6, 8,10,13,15,16]. 16 121 Understanding the mutual influence of genetics and environmen­ tal factors arouses interest in establishing the "critical or sensitive" periods of development. During sensitive periods higher sensitivity towards external factors appears. At certain periods environmental factors have an optimum influence on the development. At other periods the influence can be neutral or even negative. Being aware of the critical periods and the amount of optimum training effect, we can regulate individual characteristics of the organism at different periods of ontogeny and guide the individual development [1, 5,15]. Numerous researches have shown that several morphological char­ acteristics are generally determined. In spite of the fact that morpho­ logical development undergoes important changes during different age periods, it is more or less stable and therefore it is possible to use morphological characteristics for prognosis at all ages. The role of the genotype increases constantly since birth and reaches its peaks during the period of sexual maturity [4,6,8,9,15]. There are also optimum periods of growth in the development of functions of movements and their fixation. During this period certain functions get fixed best. Missing this timing can result in slow or bad formulation of these functions. It takes more time and the results are instable. That is the reason for starting the mastering of one or another activity at the optimum age [3,11,15,16]. The importance of sensitive periods in sports is essential in deter­ mining the specializing age, morphological readiness, optimum train­ ing load, formulating intellectual activities etc. Research has shown that when developing the abilities according to one's aim, the greatest effect is achieved in the period when their natural growth is highest. Using the same methods, the same load and intensity in the train­ ing gives different pedagogical effect in various periods. It is biggest during the period of the most intensive growth. Working upon phys­ ical abilities by training in the stage of faster development leads to a noticeable rise of these abilities. The bigger the natural increases or physical preparation are, the greater is the effect provided by training the abilities in their critical stage. As a result, the maximum growth of abilities is achieved. At the same time the basis for the future development dynamics of various physical abilities is established. In case of early specialization and intensive training, without be­ ing aware of the anatomical and physiological characteristics of the organism and the duration and nature of sensitive periods, there is the danger that we do not fully realise the potential of the organism. Health problems and hindrance of the natural development cannot be excluded either [2,3, 4, 6, 8,12,13,15,16]. 122 Methodology Proceeding from the above-mentioned considerations, the follow­ ing aim was set to the research programme: — to establish the sensitive periods of the physical development of Estonian schoolchildren of both sexes. The research was carried out among Estonian adolescents. Boys within the age limit of 11-18 and girls of 10-17 were tested. According to their age, they fell into the following groups: Age 10 11 12 13 14 15 16 17 18 Boys 317 344 365 350 341 286 230 197 Girls 144 198 170 142 122 123 99 83 The following tests were applied to grade the main abilities: maximal strength — back muscle strength measured with dy- namometre; explosive strength or power — standing long jump, vertical jump, pushing a medicine ball (2 kg) from chest in the sitting position; running — 30 m race. Results and Discussion The sensitive periods of physical development were established according to the annual growth rate. In Table 1 the annual growth in­ crease or static strength (back dynamometria) is shown in percentage of the total growth in boys at the age of 11-18 and girls of 10-17 years. T a b l e 1 Annual growth increase in the back dynamometria (% of the total growth) Age 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 Boys - 4.0 7.6 17.5 23.4 19.9 14.7 12.9 Girls 11.8 20.5 19.2 9.5 12.6 9.5 16.7 The research shows that the sensitive period of static strength development in boys was at the age of 13-16. The greatest increase occurs in the years 14-15 (23.4% of total growth). Among the girls the sensitive period of static strength development was at the age of 11-13 (39.7% of the total growth). 16* 123 T a b l e 2 Annual growth increases in the standing long jump (% of the total growth) Age 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 Boys - 6.8 14.0 18.8 18.9 16.7 13.0 11.8 Girls 28.5 53.4 2.3 8.7 4.2 2.3 0.6 Table 3 Annual growth increases in the vertical jump (% of the total growth) Age 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 Boys - 4.9 14.4 13.0 18.5 21.2 15.5 12.5 Girls 40.5 36.7 7.6 2.5 2.5 7.6 2.5 T a b l e 4 Annual growth increase in pushing medicine ball (2 kg) from the chest in the sitting position (% of the total growth) Age 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 Boys - 8.1 11.9 17.9 18.5 16.6 16.5 10.5 Girls 19.3 20.5 26.0 9.7 7.3 15.0 12.0 z_ In Tables 2,3 and 4 the annual growth increases of power (standing long jump, vertical jump and pushing the medicine ball from the chest in the sitting position) are shown for both sexes. Tables 2 and 3 show that the. sensitive periods of legs power de­ velopment was at the age of 12-17 years in boys. The biggest annual growth rates occur at the age of 13-16. In girls the sensitive periods of legs power development was at the age of 10-12. During these 2 years (10-11 and 11—12) 81.9% of standing long jump and 77.2% of vertical jump results occur out of the total growth at the age of 11-17. Ikble 4 shows that in boys the sensitive periods of hands power development was at the age of 13-17 and in girls at the age of 10-13. Table 5 gives the sensitive periods of running speed development. In boys the sensitive period is at the age of 12-17 and in girls of 10-13. In girls the sensitive period mainly falls on the period of 10-13 years of age. Our research has shown that the sensitive periods of different physical abilities are concentrated in boys on the age of 12-17 and in girls on the age of 10-13. Henceforth emphasized attention should be paid to developing the abilities at the given age levels. It results in 124 T a b l e 5 Annual growth increases in running speed (m/s) Age 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 Boys - 0 20.0 20.0 20.0 20.0 Ж0 0 Girls 50.0 25.0 25.0 0 0 0 0 0 the maximum increase of abilities. Conclusion 1. Our research has shown that the sensitive periods of static strength, power and running speed development are at the age of 12-17 in boys and 10-13 in girls. Static Power Running strength Legs Hands speed Boys 13-16 12-17 13-17 12-17 Girls 11-13 10-12 10-13 10-13 2. Special attention should be paid to the development of the abilities that were examined in certain age groups (sensitive periods) because training during these periods leads to the maximum growth of abilities. 3. Awareness of the critical periods enables us to explain the pro­ cess of physical preparation of students of different age and sex scien­ tifically, to determine the optimum growth for specialization and to plan the training schedule of young sportsmen. REFERENCES 1. Kohoutek, M. A contribution to the conception of sensitive periods. 3. Sports Kinetics '93. Poznan, 1993, 64. 2. Malina, R., Bouchard, C. Growth, maturation and physical activity. Illi­ nois: Champaign, 1991, 443-464. 3. Бальсевич В. К. Исследование локомоторной функции в по­ станальном онтогенезе человека [5-65 лет]. Докт. дисс. М., 1977. 4. Башкиров П. Н., Лутовинова Н. Ю., Уткина Н. И., Чтецов В, П. Строение тела и спорт. М., 1968. 125 5. Вриль М. С., Клецёв Ю. Н. Использование модельных харак­ теристик волейболистов высшей квалификации в процессе отбора спортивные школы. М., 1968. 6. Булгакова Н. Ж. Отбор и подготовка юных пловцов. М., 1986. 7. Зациорский В. М., Сергиенко JI. П. Влияние наследственности и среды на развитие двигательных качеств человека. — Теория и практика физической культуры, 1975, 6, 22-29. 8. Кузнецова 3. И. Развитие двигательных качеств у школьников. М., 1967. 9. Сергиенко JL, Алексеева С. Спортивный отбор. — Лёгкая атле­ тика, 1979, 12, 4-5. 10. Сергиенко Л. П. Исследование влияния наследственных и аре­ довых факторов на развитие двигательных качеств человека. Канд. дисс., 1975. 11. Сергиенко Л. П., Алексеева С. В. О генетических предпосыл­ ках к развитию гибкости. — Теория и практика физической куль­ туры, 1978, 6. 5-12. 12. Сергиенко Л. П. Половые особенности наследственности и среды на развитие двигательных качеств человека. — Теория и практика физической культуры, 1980, 3, 15-19. 13. Шапошникова В. И., Портнов Т. Т., Цветков В. Т. Темпы прироста показателей физических качеств у детей и подростков. — Возраст и становление спортивного мастерства. Смоленск, 1974. 14. Шварц В. В. Генетика и спортивная специализация детей и под­ ростков. — Медицина, подросток и спорт. Смоленск, 1975, 54-67. 15. Шварц В. В., Хрущёв С. В. Медико-биологические аспекты спор­ тивной ориентации и отбора. М., 1984. 16. Филин В. П. Теория и методика юношеского спорта. М., 1987. 126 CARRIAGE ON THE PERIOD OFPREGNANCY R. Linkberg Institute of Sports Pedagogy, University of Tartu, 18. Ülikooli Street, Tartu, EE2400, Estonia Bearing of a person is the basis for carriage. During the lifetime, the spine shapes itself according to the individual's moving or holding of the posture. If the posture is correct, the load which falls on the muscles is balanced. Such posture doesn't tire or cause any troubles. The right carriage is guaranteed by trained muscles of the stomach, buttocks, back and legs. The bearing of a woman of good carriage is natural and free. The centres of shoulder, hip joint and heel are on the same vertical. Legs are straight from the knees, the look is straight, shoulders free of tension, hands down [4]. During pregnancy the natural curves of the body are amplified because the place of the centre of gravity changes and by the agency of hormones the stability of joints. The centre of gravity of the body moves forward, the load on the spine grows bigger. To balance the body, the woman tends to stand back on her heels, pushing also her hips back too far. In this case, back muscles are too much pressed together and overstrained. Stomach muscles stretch out and losen and the result is a saddle-like back and backache. Keeping the pos­ ture right during pregnancy is made difficult also by the fact that by the agency of hormones joint ligaments soften, joints become more movable. If the stomach and buttock muscles are not strong enough, they are not able to keep the pelvis in the right position and the result is the wrong bearing as mentioned above.. In the case of wrong car­ riage, wrong tension may arise also in the shoulder girdle if the head is dropped to the breast and shoulders are moved forward to balance the body. In this case breast kyphosis is increased. Thorax is sunken and breathing becomes more difficult. To maintain the right posture the stomach muscles must support the stomach from the front and buttock muscles must quarantee the right angle of inclination of the pelvis so that the pelvic girdle would stay exactly below the shoulder girdle [1, 2, 3,5, 6, 7]. The aim of the investigation was to study the dynamics of the changes of carriage during pregnancy and compare the carriage of nonpregnants with the carriage of pregnants. 127 Methods 57 women in primary pregnancy at the age of 17 to 31 (average 22.2 ± 0.3 years) were investigated. To characterize the carriage, the profile of the spine was drawn both in standing at ease and at attention. The Abalakov contourograph was used. The exact but lessened shape of the spine was got [9]. To get further data, the 7th cervical vertebra was taken as the central point from where a prependicular was drawn and the following characteristics were determined: A — the 7th cervical vertebra; К — distance between the peak of kyphosis and the perpen­ dicular; KK — distance (mm) between the К characteristics and the 7th cervical vertebra of the spine on the perpendicular; L — distance between the peak of lordoses and the perpendic­ ular (if L intersects the perpendicular, it has a + mark, if it doesn't intersect, it has a - mark); LK — distance between L characteristics and the 7th cervical vertebra of the spine on the perpendicular; KÜ-LO — straight line which joins the peaks of kyphosis and lordos­ es; straight line of sacrum — the extension of the projection of the sacrum; KÜ-LO angle — the angle between the straight lies of KÜ-LO and the sacrum (Figure 1). KK /_ KY-LO Fig. 1. The profile of the spine. 128 The measurements were carried out on the 13th, 20th, 32th and 38th week of pregnancy. As comparative data, U. Sahva's [9] data about the carriage of female students were used. In the analysis of correlation the coefficients whose absolute value was bigger than 0.5 were taken under observation. Results 1. Comparison of ordinary carriage and carriage during pregnancy. On the analyses the data obtained from carriage measurements on the 38th week of pregnancy were used. The results are shown in Table 1. Comparing the carriage during pregnancy with the ordinary one, the following differences can be brought out. The size of kypho­ sis (K) of an ordinary carriage was 12.12 ± 4.89 mm, on the pregnant 14.22 ± 5,2 mm; the distance of the peak of kyphosis from the 7th cer­ vical vertebra (KK) 61.1 ± 19.9 mm and 58.3 ± 14.31 mm respectively. The size of lumbar lordosis in ordinary women was 3.04 ± 6.49 mm, in the pregnants -2.93 ± 12.0 mm, the distance of lordoses from the 7th cervical vertebra (LK) 152,6 ± 12.5 mm and 150.1 ± 8.0 mm respectively. T a b l e 1 Characteristics of the carriage of non-pregnants and pregnants in standing at ease and at attention x ±5 Non-pregnants Pregnants at ease at attention at ease at attention К 12.12 ± 4.89 8.04 ± 4.4 14.22 ± 5.2 12.0 ± 6.8 KK 58.38 ± 14.31 49.67 ±17.64 61.1 ± 19.9 63.4 ±16.6 L 3.04 ± 6.49 5.53 ± 6.88 -2.9 ±12.0 -3.15 ± 8.7** LK 152.62 ± 12.51 146.65 ± 13.6 150.1 ± 8.0 137.3 ± 38.6 KÜLO angle 150.67 ± 7.99 149.99 ± 8.37 154.3 ± 7.0 154.0 ± 6.9* * — statistically significant difference (p < 0.05) in relation to non­ pregnants; ** — statistically significant difference (p < 0.01) in relation to non­ pregnants. In the case of standing at attention the changes were going in the same direction as in the case of standing at ease, but the shift was more noticeable. The pregnant has a bigger kyphosis (p < 0.01) and a longer distance of kyphosis from the 7th cervical vertebra (p < 0.001), a smaller lumbar lordosis (p < 0.001) and a shorter distance of lordosis from the 7th cervical vertebra (p < 0.001). The angle of inclination of kypho-lordosis is bigger (p < 0.01). 17 129 2. Dynamics of the carriage changes during the different periods of pregnancy. Observing the changes of carriage during the 38 weeks of pregnan­ cy we may notice the following (Table 2). In standing at ease there was a tendency towards the increasing of kyphosis on the 20th week of pregnancy. In other periods the size of kyphosis did not differ from the one at the beginning of pregnancy. KK practically did not change during pregnancy. On standing at ease there was a tendency towards the lessening of the saddle-like back at the lumbar region. LK was the shortest on the 20th week of pregnancy (139.1 ± 30.9 mm p < 0.05). In other periods LK did not differ from the one at the beginning of pregnancy. The angle of kypho-lordosis on standing at ease practically did not change during pregnancy. On standing at attention no statistically significant change of kyphosis was observed, although there was a tendency towards the increasing of kyphosis. If compared with the one in standing at ease, it was smaller (p < 0.01). KK was the smallest in the I (p < 0.001), the biggest in the III period (p < 0.001). Lordosis was the biggest on the 20th week of pregnancy (5.0 ± 29.1 mm, p < 0.05) and the smallest on the 38th week (-3,15 ± 8.7 mm, p < 0.001). LK was the same in the 1st, 2nd, 4th periods of measurement, in the 3rd period there was a tendency towards the increasing of the LK The biggest angles of inclination of kypho-lordosis was registered in standing at attention in the 20th (152.8 ± 15.2 mm, p < 0.05) and the 38th (154± 6.91 mm, p < 0.05) week of pregnancy. Correlation analyses brought out the following correlations (Figure 2). kyphosis in standing at attention 0.654 kyphosis in standing at ease -0.684 lordosis in standing 0.589 lordosis in at ease standing at attention -0.522 angle of the inclination of kypho-lordosis in standing at ease Fig. 2. Correlational relations of the characteristics of the carriage. 130 X> oo \о чо ON Л H о-Н •-Н» -ДН С-TЛI о-Н 7О3 cгнi \с0п fy сго-: in •М •Й ^ & 2 oo iri Tf in «Ё «Я «Я d> Q> 2> „<йЦ 5 6 5 te ""! ON " э O 4 i—N< I О О О rHN с С с 0> •H-H-H -H-H .2 .2 -2 pfi ts _сз J2 тз 00 c ü Сtu С о и Н а U>H СаUH) ON <L ON vo 00 V") ^ S Ö es VO vi СО СО о -4 xf ЧО CS CS Оtfr II '3и I о о ХО оо xh Й» Я О h h o\ ^ со г- со чо t> 1—1 xf •в — es о ö Ö об о Ö о о oi vo' ÖT—I CS CO t0-40 -г! > СО -H -H -H -H -H -H -+нi -нH 41 -н -н 41 41 S ? (2 с Ох ЧО xh 00 Е Ь V) CS ЧО ̂00 VO 5 с 2 5 ю оо V) •a s xf *"H i—4 Xf О хГ о со О 00 es in .ä 2 rfj iri 00 N xf |ч es о Г-Н об ö ö Ь съ о Щ О > <г-s~ v> 15- -H-H-ti-H-H-H -нH -н -н -н 41 4i 41 xt- in оо г- со 00 В.-о <4 t**; О Vi Vy Ox <с in ЧО t> CS I § rl XC Ö r-i ox 0\ in xf CS СО ö 04 -4 *Ч ** S3 н О ЧО CS гЧ H0\ гЧ Я .£• я — <Яи "ов в © ф Ä =ä 00 oo Eо -o*o оÄ оО о о V V y o u CL О. во" 4> « ^ ̂ Я Q * * * * <Я ̂PQfca, a. U К The mean absolute and relative (per 1 kg body weight) value of PWC170 was significantly lower in both control groups (Table 1). If compared with others the PWCiTo/kg was relatively high in both active and inactive young and middle-aged females (21]. There were no significant differences in the blood lipid and lipopro­ tein concentrations between active and inactive groups (Table 1). There are data available that only relatively high running training loads (30 miles/week) may increase HDL-C concentrations in the blood in females [18] and as a rule, moderate exercise did not cause changes in HDL-C and LDL-C concentrations [1,11]. It is well-known that women have normally higher values of HDL-C than men [4]. It seems reasonable to infer than moderate physical activity does not cause sig­ nificant changes in blood lipid and lipoprotein concentrations in the blood in either young or middle-aged females. We must conclude that there are no significant differences between the moderately trained and untrained young and middle-aged groups of females in blood lipid concentrations. On the other hand, the physical activity increased physical working capacity. ACKNOWLEDGEMENTS. The author would like to thank the BODYSTAT LIMITED (GREAT BRITAIN) managing director I. J. Meeuwsen for his help with the apparatus for measuring body composition. REFERENCES 1. Ballantyne, D., Claris, A., Dyker, G. S. Prescribing exercise for the healthy; assessment of compliance and effects on plasma lipids and lipoproteins. — Health Bull., 1978, 32,169-176. 2. Berg, A., Keul, J. Influence of maximum aerobic capacity and relative body weight on the lipoprotein profile in athletes. — Atherosclerosis, 1985, 55,225-231. 3. Berlin, J. A., Colditz, G. A. A meta-analysis of physical activity in the prevention of coronary heart disease. — Am. J. Epidemiol., 1990, 132, 612-628. 4. Carlson, L. A., Ericsson, M. Quantitative and qualitative serum lipopro­ tein analysis. Part 1: Studies in healthy men and women. — Atheroscle­ rosis, 1975, 21,417-433. 5. Cooper, К. H., Pollock, M. L., Martin, R. P., White, S. R., Linnerud, A, C., Jackson, A. Physical fitness levels vs. selected coronary risk factors. — JAMA, 1976, 236,166-169. 6. Dufaux, В., Assmann, G., Hollmann, W.P lasmalipoproteins and physical activity. A review. — Int. J. Sport. Med., 1982,3,123-126. 7. Friedewald, W. Т., Levy, R. I., Fredrickson, D. S. Estimation of the con­ centration of low-density lipoprotein cholesterol in plasma, without use of preparative ultracentrifuge. — Clin. Chem., 1972,18,499-509. 144 8. Пщтш, M., Oishi, К., Ishii, К., Iwaoka, К., Matsuo, S., Kobayashi, S., Ta mai. Т., Tafcai, H., Nakai, T. Plasma lipid and lipoprotein profile in elderly female runners. — Clin. Physiol., 1991,11,545-552. 9. Kannel, W. Вч Sorlie, E D. Some health benefits of physical activity. The Framingham study. — Arch. Int. Med., 1979,139, 857-861. 10. Lapidos L., Bengtsson, C. Socioeconomic factors and physical activity in relation to cardiovascular disease and death: a 12-year follow-up of participants in a population study of women in Gothenburg, Sweden. — Br. Heart J., 1986,55,295-301. 11. Lewis, S., Haskell, W. L,, Wood, R D. Effects of physical activity on weight reduction on obese middle-aged women. — Am. J. Clin. Nutr., 1976, 29, 151-156. 12. Lokey, E. A., Thin, Z. V. Effects of exercise training on serum lipid and lipoprotein concentrations in women: a metaanalysis. — Int. J. Sports Med., 1989,10,424-429. 13. Marti, В., Ikiomilehto, J., Salonen, J. Т., Puska, E, Nissinen, A. Relationship between leisure-time physical activity and rist factors for coronary heart disease in middle-aged Finnish women. — Acta Med. Scand., 1987,222,223-230. 14. Montoye, H. J., Block, W. D., Gayle, R. Maximal oxygen uptake and blood lipids. — J. Chron. Dis., 1978, 31,111-118. 15. Paffenbarger. R. S., Hyde, R. Т., Wing, A. L. Physical activity, all-cause mortality, and longevity of college alumni. — N. Engl. J. Med., 1986,314, 605-613. 16. Patton, J. F., Vogel, J. A., Bedynek, J., Alexander, D., Albright, R. Coronary risk factor screen and aerobic capacity in a cohort of over 40 aged military personnel. — Med. Sei. Sports, 1982,14,170P. 17. Powell, К. E., Thompson, R D., Caspersen, C. J., Kenrick, J. S. Physical activity and the incidence of coronary heart disease. — Ann. Rev. Public Health., 1987,8,253-287. 18. Rotkis, Т., Boyden, T. W., Pamenter, R. W., Stanworth, R. W., Wilmore, J. High density lipoprotein cholesterol and body composition of female runners. — Metabolism, 1981,30, 994-995. 19. Salonen, J. Т., Puska, E, Tuomilehto, J. Physical activity and risk of my­ ocardial infarction, cerebral stroke and death. — Am. j. Epidemiol, 1982, 115,526-537. 20. Schnabel, A., Kindermann, W. Effects of maximal oxygen uptake and different forms of physical training on serum lipoproteins. — Eur. J. Appl. Physiol., 1982, 48, 263-268. 21. Seliger, V., Bartunek, Z. Mean values of various indices of physical fitness in the investigation of the Czechoslovak population aged 12-55 years. Praha: CSTV, 1976. 22. Shephard, R. J. Exercise in coronary heart disease. — Sports Med., 1986, 3,26-49. 19 145 THE BLOOD LIPID AND LIPOPROTEIN CONCENTRATIONS AND FLEXIBILITY (PRELIMINARY STUDY) Hein, Т. Jürimäe, *E. Pihl Institute of Sports Pedagogy, *I nstitute of Public Health, University of Tartu, 18. Ülikooli Street, Tartu, EE2400, Estonia Introduction Numerous studies have reported of associations between plas­ ma lipid and lipoprotein concentrations and coronary heart disease [CHD, 3, 9]. A positive relationship between serum total choles­ terol (CHOL) and low-density-lipoprotein cholesterol (LDL-C) and a negative correlation between high-density-lipoprotein cholesterol (HDL-C) and CHD risk have been established [4]. The relevant components of fitness are aerobic, muscular and mo­ tor abilities and flexibility. Especially regular aerobic exercises in­ crease physical fitness, improve lipid metabolism and reduce body fat, in total decrease CHD risk. There is no direct evidence to show a significant relationship between blood lipid concentrations and flex­ ibility. It is well-known that habitual physical activity improves the structure and function of ligaments, tendons and joints [7]. On the other hand, the individuals are likely to have a lower risk of orthope­ dic injuries and lower back problems if they have normal flexibility. The loss of flexibility may result in serious muscoloskeletal problems that can result in poor posture and excessive pain [1]. Are there any relationships with atherosclerotic processes? The purpose of this research was to study the relationships between blood lipid and lipoprotein concentrations and flexibility in middle- aged males and females. Methods The subjects were 21 middle-aged (40-50-year-old) males (n = 7) and females (n = 14). Flexibility measurements. The active range of motion (ROM) of the neck joint was measured by the gravity goniometer according to 146 the positions of AAOS [7]. For measuring the neck extension and flexion (ROM) the instrument was fastened to the side of the head over the ear (auditory meatus). The scores for neck flexion were taken when the subject lowered the head forward to a position as near to the chest as possible and the neck extension when the head was lowered to the backward maximum position. For measuring the lateral flexion to the left and right directions the instrument was fastened to the head so that its center was aligned with the occiptionasal line. The scores for lateral neck flexions were taken with the head moved to both directions as far as possible. For measuring the neck rotation the instrument was fastened on the top of the head and the center of the instrument was aligned with the occiptionasal line. The subject was in a supine position on a bench so that head and neck projected over the edge of the bench. The scores for left and right rotation were taken when the head moved to both direction as far as possible. For measuring the shoulder flexion and extension the instrument was fastened to the lateral side of the left upper arm and the center of the instrument was on the line joining the lateral epicondyle of the humerus and the glenohumeral joints' centre. The subject was in the standing position at a projecting corner of a wall. The scores of the extension and flexion were taken when the arm moved accordingly downward and backward and forward and upward. For measuring the shoulder rotation the instrument was fastened to the left ulnar side of the forearm and the center of the instrument was on a line from the decranon process to the ulnar styloid process. The subject was in a standing position of a corner of a wall. Blood samples. Venous blood samples were enzymatically ana­ lyzed for total cholesterol (CHOL), high-density-lipoprotein choles­ terol (HDL-C), triacylglycerols (TG) and glucose (GL). The low- density-lipoprotein cholesterol (LDL-C) was calculated using the Friedewald et al. [5] equation, the ratio of HDL-C/CHOL was calcu­ lated, too. Statistical analysis. Standard SYSTAT statistical packages were used for estimating means and standard deviations. Pearson prod­ uct — moment coefficient of correlation between test scores were established. Results and discussions The subjects mean blood lipid and lipoprotein concentrations are presented in Table 1. If compared with others [8] we must conclude that the mean concentration was relatively low. Nobody of our sub­ jects was hyperlipidemic. The flexibility of the neck and shoulder are presented in Ta- 19* 147 Table 1 The mean blood lipid and lipoprotein concentrations and neck and shoulder flexibility parameters of the subjects (x ± SD) CHOL( mmol • 1_1) 4.27 ± 0.40 HDL-C (mmol Г1) 1.54 ± 0.31 LDL-C( mmol Г1) 2.46 ± 0.58 TG (mmol Г1) 0.73 ± 0.22 HDL-C/CHOL ratio 36.2 ± 1.3 Neck flexion (degrees) 54.95 ± 13.10 Neck extension (degrees) 81.81 ± 18.51 Neck lateral flexion to the right (degrees) 49.52 ± 13.52 Neck lateral flexion to the left (degrees) 45.00 ± 5.81 Neck rotation to the right (degrees) 79.05 ± 12.22 Neck rotation to the left (degrees) 84.10 ± 9.52 Shoulder flexion (degrees) 183.00 ± 17.71 Shoulder extension (degrees) 56.86 ± 27.00 Shoulder internal rotation (degrees) 159.71 ± 17.00 Shoulder external rotation (degrees) 28.00 ± 12.10 ble 1. The mean results were relatively similar with the others [6, 10]. The results of the correlation analyses indicate that there are significant relationships between neck rotation to the left and CHOL (r = -0.567), LDL-C (r = -0.644) concentrations and HDIVCHOL ra­ tio (r = 0.605). The neck rotation to the right correlated significantly with CHOL (r = -0.544) and LDL-C (r = -0.498) concentrations on the blood. The mechanism of the relationships is not known. Maybe it is possible to explain it with the fact that the flexibility is dependent on the elasticity in muscle fibers and tendons [2]. In conclusion, mostly the neck flexibility has a close relationship with different blood lipid and lipoprotein concentrations. The in­ fluence of flexibility to the different CHD risk factors needs more research. REFERENCES 1. Battie, M. C., Bigos, S. J., Sheehy, A., Wortley, M. Spinal flexibility and individual factors that influence it. — Phys. Ther. 1987, 67,653-658. 2. Bonns, J. Importance of flexibility in overall physical fitness. — Int. J. Phys. Ed., 1984,5,39-47. 3. Castelly, W. P. Epidemiology of coronary heart disease: the Framingham study. — Am. J. Med., 1984,76,4-12. 4. Dufaux, В., Assmann, G., Hollmann, W. Plasmalipoproteins and physical activity. A review. — Int. J. Sports Med., 1982,3,123-126. 148 5. EYiedewaSd, W. Т., Levy, R. I., Fredrickson, D. S. Estimation of the con­ centration of low-density lipoprotein cholesterol in plasma without use of preparative ultracentrifuge. — Clin. Chem,, 1972,18, 499-509. 6. Germain, N. W., Blair, S. N. Variability of shoulder flexion with age, activity and sex. — Am. Corr. Ther. J.,. 1983,37,156-160. 7. Habley-Kozey, C. L. Testing flexibility. — Physiological testing of the high performance athlete. Second Edition. Eds. J. D. MacDougall, H. A. Wenger, H. J. Green. Champaign, Illinois: Human Kinetics Books. 8. Manninen, V., Elo, M. O., Erick, H. et al. Lipid alterations and decline in the incidence of coronary heart disease in the Helsinki Heart study. — JAMA, 1988,260,641-648. 9. Miller, G. J., Miller* N. E. Plasma high-density lipoprotein concentration and development oft he ischaemic heart disease.—Lancet, 1975,1,16-19. 10. Murray, M. P., Schoukfcr, R. T. Motion and muscle strength of normal men and women in two age groups. —CIm. Qrthop. Rel. Res., 1985,192, 268-273. 149 A PILOT STUDY OF INTERRELATIONS BETWEEN GROWTH, FITNESS DEVELOPMENT AND SEXUAL MATURATION IN 10 TO 14 YEAR OLD GIRLS A. Voiver Institute of Sports Pedagogy, University of Tartu, 18. Ülikooli Street, Tartu, EE2400, Estonia Abstract The study was aimed to compare the growth and physical fitness level with the stadium of sexual maturation in 10 to 14-year old girls. Subjects were 58 girls, divided into 3 groups by Tanner's stages (I, П or III). In addition to anthropometric measurements the persons performed 9 fitness tests in January and May. Significant differ­ ences were found between girls of stages I and III in height,w eight, sitting height, chest, suprailiac and bicondyiar circumferences, and biacromal, bicristal and bicondyiar breadths. Between stages II and III significant differences were in sitting height, biacromial and bicristal breadths. Significant differences were found in skinfold measured at medial thigh and on the abdomen. The differences between results of fitness tests were insignificant in January. In May significant improvements in results of the 4 x 9 m shuttle-run were detected in stadium II and of the 20 m run in stadium III. In conclusion, the development of physical abilities is different in various stadiums of sexual maturation. Introduction The uniform organization of physical education ignores biological age and sensitive periods of the individual ontogenesis [10,17]. It has been demonstrated that the training effect is most pronounced when exercises influence a concrete physical ability in the sensitive period of ontogenetic development of functions constituting a background for the ability [6, 8]. The sensitivity of ontogenetic development to influ­ encing factors may alter during sexual maturation. A great variability has been found in trainability of aerobic work capacity in prepubescent girls [1,2,14,19]. At least in part this variability can be related to the 150 dynamics of sexual maturation. A comparatively low aerobic train- ability before puberty has been reported [1]. It was suggested that the increase in absolute values of maximal oxygen uptake prior to the age of peak height velocity is caused by growth in body size with only a negligible effect of such factors as physical activity [15]. Accordingly an increased maximal oxygen uptake response to training was found at the time of the adolescent growth spurt [12]. In prepubescent chil­ dren dynamic strength training is less effective than in older children [20]. In girls a pronounced increase in strength occurs during the peak of height velocity [5,]L These results constitute a background for the hypothesis that the effect of physical education varies1 in depen­ dence of stadiums of sexual maturation. This pilot study was aimed to compare the growth and! physical fitness level with stadium of sexual maturation in 10 to I4-years old girls. Material and methods Subjects were 5S girls of 10 to 14-years old. None of the subjects suffered from chronic diseases. They were considered to be practically healthy by the medical control in school. Subjects participated in school physical education twice in week. The studied girls did not participate in sports training. Physical education classes consisted of exercises for improved en­ durance, skill, coordination, flexibility, speed and power. Various gymnastic exercises, including aerobic gymnastics and acrobatics, as well as running, skiing, jumping were used. Methods: The degree of sexual maturation was evaluated by Tan­ ner's stages [18] and bone age. The latter was evaluated by x-ray picture of the wrist [7]. Growth was assessed by height, weight, sitting height (up to the suprailiac level), chest, suprailiac and bicondylar circumferences, biacromial, bicristal and bicondylar breaths. Skinfold was measured at 7 points on the right side of the body, using a caliper produced in University of Tartu (Estonia). The fitness tests were Cooper's test, Harvard step-test, 4 x 9 m shuttle run, 20 m run, sit-ups in 30s, squats in 30s, trunk forward flexion, and standing broad jump. Fitness test was performed in January and again in May. After the Cooper test, the heart rate recovery was estimated by an index analogical to the Harvard step- test index [11]. Statistics: The results were analyzed with the aid of the ANOVA procedure. 151 AGE BODYWEIGHT 16 60 1 4 4̂ 5 0 12 - z_7 ь о 4 0 g 10 I- ai £•4 8 3 0 - 6 20 4 10 2 0 -И Ld Lc 0 1 2 3 1 2 3 HEIGHT SITTING HEIGHT 180 3 0 160 Pf 2 5 140 „ 120 20 В ° 100 1 5 80 60 10 4 0 5 20 0 \Л У 1 О 1 2 Fig. 1. Age, weight, height and sitting height (up to suprailac level) in de­ pendence on the maturation stadiums. Numbers under the columns indicate the stages. Means ± SEM are indicated. Results According to Tanner's criteria the stage I was detected in 23 girls, stadium II in 22 girls, and stadium III in 13 girls. Significant differences were found between girls of stages I and III in height, weight, sitting height (Fig. 1), chest, suprailiac and bicristal circumferences, and biacromal, bicristal and bicondylar breadths (Fig. 2). Between stages II and III significant differences were found 152 .ад <о и II и \E о У ffl I I L 1 [ 1 1 I I *Л Q «Л О t/t О VI о О СП 0.05, Figure IB). During the second test after the 20 minute rest the duration of static work was accordingly: 70.8 ± 2.8 s and 73.6 ± 4.6 s (p > 0.05). Before the static work in a resting state systolic and minute heart volumes and frequency of heart contractions (Figures 2, 3, 4) were 77.0 ± 7.0 ml, 5.1 ± 0.5 liters/min, 66.0 ± 3.0 beats/min (holding the equipment), 71.0 ± 3.6 ml, 5.0 ± 0.3 liters/min, 70.0 ± 3.0 beats/min (without holding the equipment). 160 F(N) t(s) 800 ' * , 700 70 I i -fa 600 60 i % ш 1 i Holding Not holding Holding Not holding the equip­ the equip­ the equip­ the equip­ ment ment ment ment Fig. 1. Maximum determined force of shin muscles( A) and static work du­ ration (B). I I - The first test I / / / / I - T h e s e c o n d t e s t a f t e r 2 0 m i n beats/min. 100 80 1 «л 60 'S I 0 (min) (min) Fig. 2. Dynamics of heart contraction frequency. - Holding the equipment - Not holding the equipment I I - The first static work I / / / / I -T h e s e c o n d s t a t i c w o r k 21 161 Indices of systematic circulation of the blood after static work: systolic, minute heart volumes and frequency of heart contrac­ tions when holding the equipment increased up to 107.0 ± 8.0 mi 20.4 ± 0.8 liters/min, 98.0 ± 4.0 beats/min. Without holding the equipment accordingly: 206.0 ± 7.0 ml, 8.7 ± 0.6 liters/min, 82.0 ± 4.0 beats/min. When persons under investigation were holding the instrument during the first and second minutes after static work, systolic and minute heart volumes were smaller and recovering was quicker than with persons who were holding the equipment. Frequen­ cy of heart contractions when holding the equipment was essentially bigger (p < 0.025, Figure 2) only after the static charge. Before the second static work in both tests indices of systematic circulation of the blood were the same, as before the first one in a rest­ ing state. After the repeated static work the systolic and minute heart volumes and frequency of heart contractions also increased. After the second static work systolic and minute heart volumes and frequen­ cy of heart contractions were 107.0 ± 7.7 ml, 11.0 ± 0.7 liters/min, 103.0 ± 4.0 beats/min (holding the equipment). Recovery indices of systolic and minute heart volumes and fre­ quency of heart contractions were performed similarly to after the first work. Peripheral circulation of the blood (Figure 5) in working mus­ cles was activized more when persons under investigation performed a static work, by activizing foot bending muscles without holding the equipment. It increased from 2.8 ± 0.2 ml/min/100 cm3 up to 68.7 ± 4.0 ml/min/100 cm3. When persons under investigation were holding the equipment, circulation of the blood increased from 2.3 ± 0.2 ml/min/100 cm3 up to 55.4 ± 4.4 ml/min/100 cm3. Dif­ ferences of intensity in circulation of the blood were observed up to 50 seconds. In the farther course of recovery no essential differences were observed. Circulation of the blood was registered for 5 minutes and its increase more than twice was observed in both tests even on the fifth minute. After 20 minutes of static work the amount of flowing blood (before the second work) was essentially bigger when holding the equipment: 3.5 ± 0.4 ml/min/100 cm3 (p < 0.05), and without holding the equipment: 3.7 ± 0.3 ml/min/100 cm3 (p < 0.025). After the repeated charge in both tests circulation of the blood increased even more: up to 62.9 ± 4.2 ml/min/100 cm3 (holding the equipment), and 78.5 ± 4.8 ml/min/100 cm3 (without holding). Recovery character of circulation of the blood in shin muscles after the second static work was performed in similarly to after the first one. 162 Fig. 3. Dynamics of systolic heart volume. - Holding the equipment -Not holding the equipment I 1 - The first static work I / / / / I -The second static work 1 2 3 4 5 t 1 2 3 4 5 t (min) (min) Fig. 4. Dynamics of minute heart volume. - Holding the equipment - Not holding the equipment I I - The first static work I / / / / I -T h e s e c o n d s t a t i c w o r k 163 TОD ti 1 R 8 tüj S э E D Йg •вЯ &C N •5 ь E ЕО 2-5 I I 1 -8°P .S "В cd - •. S " С Од„ »ж 11 * -а § в &Е 8 cd w е- ЙУ о Js) СЛ cd 5 •5ä «e1 Х> -о Ё S 20 •**ч Л .У 53 Ss -о ~ о с 1) — *43 cd У чм ТЗ -*§Ои cd Св 4> cd .о S u у ^2 & О cd С и O ^Ü7 g3 "м §I 3 » 9" ^ Он о cd о ai 8 E О й> •у §j | -gy «•а Öcd J+3 со Cd •г о 3 0 ts Я о. и «ä i5 •i§ "° 1 1 I I ° -> 45 с g.a I •I 1> 2 » S ЕЬб -о я и ЕЙ с S >-i 26*5 § u £&Я *д õot5 £?o 6- i 2 d го I О >(U з i «Й О l > й i l х> хо> S I г° я с5 У 4> <м 9.2 l i 0 £ si в. 1 I I tem and enables to make alterations in the structure of functional preparation. With this approach it is possible to avoid the onesidedness erf the empirical-analytical way of thinking and consider the runner?s organ­ ism as a motor-functional system, with its universality, high plastic and reactive properties. REFERENCES 1. Arbeit, E, The process of training and competition in view of the per­ formances at the *92 Barcelona Games. — Elite Sports, International Conference Nov. 4th- 6th 1992. Winkte Institute for Physical Education and Sport, Wingate, Israel, 1993,5-16. 2. Boikau, R. A., Mayhew, J. L., Riner. W. E, Lussier, L. Physiological char­ acteristics of elite middle and long distance runners. — Canadian J. AppI. Sport Sciences, 7,3,1982,167-172. 3. Brnggemann, G. E Biomechanical considerations in the preparation of top level competitors.—Elite Sports, International Conference Nov. 4th- 6th 1992. Wingate Institute for Physical Education and Sport, Wingate, Israel, 1993,153-167. 4. Conley, D. L., Krabenbuhl, G. S., Burkett, L. N., Millar, A. L. Following Steve Scott: Physiological changes accompanying training. — The Physi­ cian and Sportsmedicine, 1984,12,1,103-106. 5. Danilova, N. Functional conditions: mechanisms and diagnostics. — Pro­ ceedings of Moscow University, Moscow, 1985, 286 p. (in Russian). 6. Dare, B. Specificity in training for the running events. — Track Tfcchnique Annual, 1983, 39-43. 7. Davidenko, D., Vesselovski, M., Vashtshuk, O. et al. Characterization of the functional reserve system of an athlete. — Systemic mechanisms and management of special working capacity of athletes (collection of research papers). Volgograd, 1984, 6-12 (in Russian). 8. Joyner, M. J. Modelling: optimal marathon performance on the basis of physiological factors. — J. Appi. Physiol., 1991, 70, 2, 683-687. 9. Kantola, H. Harjoittelun pohjaksi kilpailusuoritus. — Valmennus ja Kun- toilu, 1991, 2,24-25. 10. Keni, J.,Haralambia, G. The adaptation of the energy supply in muscle to physical activity. — Ergonomics, 1977, 20,5,285. 11. Korobov, A., Volkov, N. Middle-distance running. Factors of result attain­ ment. — Hack and field athletics, 1983,11, 6-8 (in Russian). 12. Maulbecker, K. Development of specific endurance. — Modern Athlete and Coach, 1987, 25,30. 13. Mishtshenko, V. Functional possibilities of athletes. — Kiev: Health, 1990. 200 p. (in Russian). 14. Nurmekivi, A. Running: adapt the method to the athlete. — Soviet Sports Review, 1988,23, 3,107-111. 15. Pate, R. R., Branch, J. D. Training for endurance sport. — Med. Sei. Sports Exerc., 1992, 24, 9, Suppl., 340-343. 173 16. Platonov, V. Unity and mutual connection between competition activity and preparation structure. — Theory of Sport, Kiev, 1987,115-116 (in Russian). 17. Verchoshansky, J. Ein neues Trainingssystem für zyklische Sportarten. — Münster: Phil ippka-Verlag, 1992,135 p. 18. Virn, A. Sports performance capacity. Tartu, 1990, 97-99 (in Estonian). 174 COST VERSUS ACCURACY: AN EXAMINATION OF THE RELIABILITY OF THREE SKINFOLD CALIPERS D. A. Brodic, M. M. Burl School of Health Sciences, University of Liverpool, Liverpool, L69 3BX, United Kingdom Abstract Twenty four young, healthy, adult females with a mean age of 19.7 years were measured at four body sites using three different makes of skinfold calipers. Readings were also taken on constant materials of solid teak and sorbo rubber. Results showed a non­ significant difference between the calipers at any site or material with analysis of variance F ratios well below the critical value re­ quired for significance at p 0.05. Introduction The matter of what percentage of body weight is composed of fat is of great interest to many people because of the medical and fitness implications. Fat content of the body may influence morbidity and mortality. It may also alter the effectiveness of drugs and anaesthetics as well as the ability to withstand exposure to cold and starvation [4]. It is therefore of special interest to doctors, athletes and coaches. Methods of making this assessment are many but two methods are generally popular because of their degree of efficiency, ease and prac­ ticality of application. These are hydrostatic weighing and skinfold measurements and much data have been collected using them. These methods are based on considering the body to consist of two major compartments. The body fat which includes entire lipids of the body and the fat-free mass which includes all the rest of the body. According to Brozek and Keys, [2], hydrostatic weighing appears to be the best single criterion, with skinfold as the next best index. Hydrostatic weighing has many disadvantages which include lim­ ited accessibility, expensive equipment and unacceptability to many subjects who are not water confident. Hence the more easily ap­ plied method of skinfold testing is being increasingly used by people 175 with specialist interest such as doctors, physical fitness specialists and coaches. Indeed simple calipers are available for individuals to do their own testing, and one of these is included in the present study. Several workers have produced regression equations to enable calcu­ lations of fat to be made from sums of skinfolds. The values produced by Durnin and Wormersly [3], for males and females 17 years to 70 years are widely used, as are more specific values such as those produced by Seltzer et ai. [9]. However, for this method to be acceptable on a scientific basis many sources of error need to be considered and eliminated. Inter- rater reliability seems to be the greatest source of error. One study by Kispert and Merrifield [7] found the reliability coefficients ranged from 0.62 to 0.85 at individual sites and clearly this is insufficiently accurate for scientific purposes. However, other workers have found higher correlations. Keys and Brozek [6] reported correlations of 0.92 to 0.96 for different testers. It would appear that training and standardisation of technique could reduce this error. Interater error gives rise to technical measurement error which varies with site chosen, experience of technician, fatness of subject and method of error estimation [5]. Regarding the site chosen, triceps and subscapular is recognised by Brozek [1] to be good predictors of body fat as well triceps by Tanner and Whitehouse [10]. The experience of the technician is of course something that applies to any skill. The fatter the subject the greater the error source due to the variability in compressibility of fat. Lohman [8] commented on four different methods of error estimation with his own method rated at 0.95. An additional source of error may be the reliability and accuracy of the equipment used. With growing interest in the topic more pieces of equipment are being introduced in various price ranges. This poses the question about cost versus accuracy. It is the purpose of this study to answer this question by examining three calipers across a wide price range. Methods All measurements were carried out by the same person. The three calipers chosen were: A. Holtain caliper — a well-established and widely used piece of equipment made of stainless steel and able to give to 0.1 mm. The cost is approximately £150. B. Ponderal caliper — made of plastic with an accuracy of reading possible to 0.5 mm. The cost is approximately £20. C. Slim Kit caliper — plastic and part of a self measurement kit with accuracy to 1 mm. The cost is approximately /10. 176 The study examined 10 trials using the three calipers on two stan­ dardised pieces of material of fixed dimensions to establish their initial validity. These were a piece of solid teak and a piece of firm sorbo rubber, to assess a solid and a flexible structure respectively. Mea­ surements were carried out at marked anatomical sites over a number of days. The calipers were then used to take measurements on 24 healthy female physiotherapy student volunteers. To reduce error, partici­ pants were all within 20% of recommended weight. None was doing regular resistive exercise which might dehydrate skin for two hours prior to testing, subjects gave age and were measured for mass and height. Descriptive statistics are shown in Table 1. Four sites were chosen and carefully measured and marked on the skin with a cross. They were: Triceps—halfway between acromion and olecranon at the midpoint of the posterior aspect of upper arm. Biceps — halfway between acromion and olecranon at the midpoint on anterior aspect of upper arm. Subscapular—immediately below the inferior angle of the scapula. Suprailiac —2.5 cm above and medial to the highest point of the iliac creast. All measurements were carried out as recommended by Tanner and Whitehouse [10], and were undertake on the left side of the body following an international convention established by anthropologists 92 years ago and re-emphasised in the protocol of the International Biological Programme [11]. The technique was standardised by using the right hand to lift a skinfold exactly at the marked site, then the left fingers and thumb took hold of this fold immediately above. The caliper was then positioned at the site of the mark on the skin and centred on the midpoint of thumb and finger nails at the neck of the fold. This fold was held whilst three measures were taken with the three calipers and only then was the fold released. Each of the four sites was examined in this way and then the whole procedure was repeated twice more. The order in which the caliper were used randomised at each of the three readings. The readings taken were to the maximum accuracy possible with each caliper. The three readings of each caliper at each site were averaged. Statistical testing of the results consisted of undertaking a one way unrelated ANOVA test with each caliper on the wood and sorbo. This was repeated for the average readings for each caliper at each site on the models. 23 177 Results Using the three calipers on wood and sorbo produced ten readings on each material with each caliper. The ANOVA showed a non­ significant difference between calipers although the Ponderal caliper produced readings which averaged 0.5 mm less than the other two (see Table 2). T a b l e 1 Descriptive statistics of student subjects Age Height in cm Weight in kg % Fat Range 18-33 155-180 50-69 19-31 Mean 19.7 168.4 58.5 25.5 S.D. 3.18 6.5 5.6 3.3 T a b l e 2 Mean values for each material A В V Wood 11.0 10.5 11 Sorbo 21.0 20.5 21 Each of the ANOVA tests for the students at each site produced F ratios well below the critical value of 2.00 and thus producing a nonsignificant results for each caliper at each site. Thus the three calipers are equally accurate and reliable and the cost therefore does not determine accuracy. Discussion It appears that all three sets of calipers are equally valid and thus it is not necessary to provide great expenditure for the purpose of skinfold testing. However, in general use of such equipment other aspects are worthy of consideration. Firstly, the durability of the equipment. The two plastic calipers may more easily be damaged by dropping them or something heavy falling on them. On the other hand the metal Holtain caliper has such a strong spring that when it is released it needs to be carefully controlled, otherwise in constant use the metal may be worn away and thus affect the accuracy. In addition this test did not investigate the durability or consistency of the spring of any of the calipers and this may need to be considered. The second 178 point which arose during the testing was that many of the subjects commented on the discomfort of the Slim Kit caliper when it was in position in spite of great care which was taken to minimise this. The reason for this was inherent in the material used and the way it was cut revealing a very sharp edge of plastic to come in contact whith the skin. This caliper was also the most difficult to read for two reasons. The scale is the same colour as the background and therefore a very good light and excellent eyesight are needed. The other reason was that it had a very small scale graduated in 2 mm divisions so that 1 mm lay between two marks, which made it difficult to interpolate. The Ponderal caliper was much easier to use and read and no discomfort was experienced on testing. This therefore was worth the extra £10 cost. REFERENCES 1. Brozek, J. Body measurements including skinfold thickness as indicators of body composition. — Techniques for measuring body composition. Eds. J. Brozek & Henshal. Washington D.C.: Nat. Acad. Sei. Nat. Res. Council, 1961, 3-35. 2. Brozek, J., Keys, A. The evaluation of leanness — fatness in man. Norms and interrelationships. — British Journal of Nutrition, 1951,5,194-206. 3. Durain, J. V G. A., Womersley, J. Body fat assessed from total body density and its estimation from skinfold thickness: measurements on 481 men and women aged from 16 to 72 years. — British Journal of Nutrition, 1974, 32,77-97. 4. Jackson, A. S., Pollock, M, L., Gettman, L. R. Intertester reliability of selected skinfold and circumference measurements and percentage fat estimates. — Research Quarterly, 1978, 49, 546-551. 5. Johnston, E E., Hamill, E V V, Lemeshow, J. Skinfold thickness of children 6-11 years. United States National Health Survey, Series II. Department of Health, Education and Welfare, 1972,120,1-60. 6. Keys, A., Brozek, J. Body fat in adult men. — Physiological Review, 1953, 33,245-325. 7. Kiepert, С. P., Merrifield, H. H. Interrater reliability of skinfold fat mea­ surements. — Phys. Therapy, 1987, 6, 917-920. 8. Lohman, T. G. Skinfolds and body density and their relation to body fatness: A review. — Human Biology, 1981, 53,181-225. 9. Seltzer, С. C., Goldman, R. F., Mayer, J. The triceps skinfold as a predic­ tive measure of body density and body fat in obese adolescent girls. — Paediatrics, 1965, 36,212-218. 10. Tanner, J. M., Whitehouse, R. H. Revised standards for triceps and sub­ scapular skinfolds in British children. — Arch. Dis. in Children, 1975,50, 142-145. 11. Weiner, J. S., Lourie, J. A. Human Biology: A guide to field methods. — International Biological Programme Handbook No. 9, Oxford: Blackwell Scientific Publications, 1969,12. 23* 179 KNOWLEDGE OF BLOOD CHOLESTEROL WITHIN AN INNER CITY COMMUNITY D. A. Brodie, J. Hammond, P. D. Slade School of Health Sciences, University of Liverpool, P.o. box 147, Liverpool, L69 3BX, United Kingdom Abstract The purpose of this study was to ascertain the knowledge of blood cholesterol issues in an inner city environment before em­ barking on a health promotion campaign. One hundred subjects completed a simple questionnaire. It was shown that 39% of the respondents had been measured for blood cholesterol with over 20% knowing their own value. A similar percentage did not know the cause of high blood cholesterol nor did they know how to lower it. A very high percentage of subjects advocated a range of ac­ tions to control high blood cholesterol, some of the actions being erroneous. The study provides baseline data against which other similar studies can be compared and also indicates the need for public education on the issue. Introduction Although the incidence of coronary heart disease (CHD) in Eng­ land has declined since the 1970s, it remains one of the highest in the world. Consequently, a primary target of the Health of the Nation [8] "to reduce death rates for both CHD and stroke in peope under 65 by at least 40% by the year 2000." With the accumulation of a plethora of evidence showing that high plasma cholesterol levels significantly contribute towards CHD, educational campaigns have attempted to increase the public's knowledge concerning this adverse relationship. A Consensus Conference [4] on the prevention of heart disease rec­ ommended that adults should know their blood cholesterol levels, and that they should aim for a target level of 5.2 mmol/1. The extent to which any recommendations are followed needs to be carefully ex­ amined and is particularly important in discovering how campaigns affect knowledge and behaviour. Many surveys have been conducted to ascertain changes over time, especially within the United States. 180 For instance, Schucker et ai. [6, 7] found large improvements during the 1980s concerning cholesterol related dietary knowledge and in­ terest in personal cholesterol levels. Niknian et al. [5] found that in 1981-1982,11.6% of residents in a New England community had their cholesterol levels previously measured. By 1987-88, this figure had increased to 16.3%. Furthermore, the percentage stating that they know their cholesterol level increased from 65% to 75% within the same time period. This particular survey therefore was designed to assess the degree of public knowledge relating to blood cholesterol m an inner city community. Method The information was based on a questionnaire completed by a face-to-face interview of approximately three minutes. It used an ac­ cidental sampling procedure. A reasonably representative cross sec­ tion of the normal demographic population was achieved by interview delegation. The questionnaire was kept short and was constructed with the intention of comparing data from similar surveys. Each subject was asked their gender, age, occupation, whether they ever had their blood cholesterol measured, if they knew the level, the effect if has on health, the cause of high blood cholesterol, whether they knew how to lower the blood cholesterol level and how, and a final question listing a number of actions to control high levels. For each of these (e.g. eat less fat) the subjects were required to respond with either "definitely help", "might help", or "would not help". The survey was conducted in a shopping centre in the centre of Birkenhead, a town of 80,000 people in the North West of England. Results and Discussion 100 questionnaires were completed with 51% of the respondents being male and 49% female. The overall mean age was 42.2 years (range 17-84 years). The mean age for males was 38.3 and for females 46.4 years. The socio-economic distribution, based on the occupation of the head of the household was as follows: 17% professional 14% managerial/technical 49% skilled 13% partly skilled 7% unskilled 181 Table 1 shows the results of the open-ended question on high blood cholesterol and health. Table 1 What effect does high blood cholesterol have oil your health Effect % of respondents Don't know 32 Heart attack/Stroke/CHD 34 Linked to the heart 14 Blocks the arteries 9 Other 11 The perceived cause of high blood cholesterol are shown in Table 2. T a b l e 2 What causes high blood cholesterol Causes % of respondents Don't know 20 Lack of exercise 4 Stress 5 Diet 25 Fats 34 Animal/saturated fats 6 Others 6 The above values indicate the need for significant improvements in the level of education. As Frank et al. [2] states: "For many in­ dividuals, cholesterol education comes from a multiplicity of sources and consists of whatever the mass media and manufacturers of 'low- fat', 'low-cholesterol', and 'high-fibre' products choose to promote". More education must be available through organised campaigns in order to promote correct information. Twenty three per cent of respondents report that they would not know how to lower their blood cholesterol level. This compares with 34% in the national survey by Schucker et al. [7]. Thirty nine per cent of respondents (41% of females and 35% of males) stated that they had their blood cholesterol measured in com­ parison with 46% in Schucker et al. [7] study population in 1986. No clear relationship existed when analysed by social class. Fifty nine per cent (50% of males; 67% of females) of those reporting that their blood cholesterol had been measured knew their own level. This cor­ responds to 22% of the total sample, compared with just 7% obtained 182 by Schuker et al. [7]. These figures are reasonably encouraging given that the Consensus Conference (1985)[ 4] emphasized the importance of all individuals knowing their level of communication between the medical professionals and the patients* and by increasing the number of measurements taken. In this survey, the majority of individuals who knew their cholesterol level had values at or above 5.2 mmol/1 (68%) suggesting that either physicians are only informing patients when their value is high, or alternatively, only those with suspected high cholesterol are undertaking tests. Table 3 Actions people might take to control high blood cholesterol level and responses Controlling actions that would 'definitely* help Response Eat less fat 94 Ttimfat 91 Eat more fish 89 Eat less sausage, bacon and luncheon meats 87 Use skimmed milk 87 Eat less cholesterol 85 Get regular exercise 85 Replace meat with poultry/fish 82 Eat less cheese 77 Avoid stress/fatigue 70 Use less salt 69 Eat fewer egges 65 Eat less sugar 58 Eat more vitamins 57 Reduce calories ^ 55 Table 3 shows ranked results from a list of actions presented to respondents that people might take to control high blood cholesterol levels. The first point of interest is that the majority of respondents (i.e. over 50%) believed that all of the actions listed would defi­ nitely help in controlling high blood cholesterol, compared with only seven of the actions in the study by Schucker et al. [7]. Further­ more, all percentages notably exceeded those obtained in the latter survey. Unfortunately it is difficult to determine whether the use of such closed questions overestimates respondents knowledge. For instance, the National Health Interview Survey of 1985 [9] in using a closed list found that 90% of respondents identified smoking as a CHD rist factor. However, Frank et al. [3] found that only half men­ tioned smoking when asked spontaneously to identify risk factors. Davison [1] stated that "the term knowledge indicates that there is a high degree of certainly in the individuals mind about the data in 183 question". Therefore, it may be more suitable to apply open-ended questions, although these may provide more "conservative measures of respondents knowledge" [3]. Of all the controlling actions, eating less fat (94%), trimmig fat (91%) and eating more fish (89%) received the greatest proportion of respondents believing that they would be effective. Less than 60% of respondents stated that they thought eating less sugar, eating more vitamins, and reducing calories would definitely help (58%, 57% and 55% respectively). In the Schucker et aL [7] study, eat more vitamins and eat less sugar were also ranked within the bottom three actions, although the percentages were considerably lower (18% and 34% respectively). These latter values would suggest an inferior knowledge base within the sample obtained in this survey, even though values for the other actions were considerably higher. Again, this is most probably explained by an overestimation of knowledge. With reference to gender, a greater proportion of women, for the majority of actions, reported that they would definitely help. The most profound differences were on the following actions: eat fewer eggs (78% of females and 52% of males); eat less cheese (88% and 66%); reduce calories (65% and 45%) and avoid stress/fatigue (76% and 64%). Frank etal. [2] found that the most consistent disparities in choles­ terol related knowledge and behaviour were education related. High­ er scores were obtained in the better educated, which were also found to improve more over time. Less education is closely associated with socioeconomic status and social class. In this particular study how­ ever, no clear pattern emerged when values were analysed by social class. To conclude, this study has measured baseline values of cholesterol knowledge on a small sample of the local population. Comparisons with the national survey conducted by Schucker et al. [7] produced favourable results, although two potential limitations exist. Firstly, the latter study took place in the United States eight years earlier. Secondly, the use of open-ended questions may significantly overesti­ mate true values. However, its use as a tool to measure changes over time may prove beneficial. REFERENCES 1. Davison, L. E. An analysis of knowledge, beliefs and behaviour relating to the development of coronary heart disease. — Health Education Journal, 1980,103-109. 184 2. Frank, F.., Winkleb}, M. A., Fortmann, S. P., Rockhill, В., Farquhar, J. W. Improved cholesterol-related knowledge and behaviour and plas­ ma cholesterol levels in adults during the 1980s. — JAMA, 1992, 268, 1566-1572. 3. Frank, E., Winkleby, M. A., Fortmann, S. R, Farquhar, J. W. Cardiovascular disease risk factors: improvements in knowledge and be­ haviour in the 1980s. — Am. J. Public Health, 1993, 83,590-593. 4. Lowering blood cholesterol to prevent heart disease. Consensus Confer­ ence. — JAMA, 1985,254, 2080-2086. 5. Niknian, M., Lefebvre, R. C., Carleton, R. A. Are people more health conscious? A longitudinal study of one community. — American Journal of Public Health, 81,203-205. 6. Schucker, В., Witter, J. R., Santanello, N. C., et al. Change in choles­ terol awareness and action: results from national physician and public surveys. — Arch. Intern. Med., 1991,151,666-673. 7. Schucker, В., Bailey, К., Heimbach, J. Т., Mattson, M. E., et al. Change in public perspective on cholesterol and heart disease. Results from two national surveys. — JAMA, 1987, 258, 3527-3531. 8. Secretary of State Health. The health of the nation. London: HMSO, 1991. 9. Thoraberry, О. Т., Wilson, R. W., Golen, P. M. Health promotion data for the 1990 objectives from the National Health Interview Survey of health promotion and disease prevention, United States, 1985. Adv. Data Vital Health Stat. — DHHS publication PHS. 1986,86-1250. 24 185 ABOUT THE POSSIBILITIES TO DETERMINE REACTION OF CONNECTIVE TISSUE'S STRUCTURES IN THE LOCOMOTIVE APPARATUS IN GYMNASTS T. Kums Institute of Sports Pedagogy, University of Tartu, 18. Ülikooli Street, Tartu, EE2400, Estonia Abstract The possibility to determine the reaction of connective tissues of the locomotive apparatus to the training load was inquired. 14 high- qualified female competitive gymnasts from age 9 to 14, took part The parameters were determined which indirectly reflect the functional state of the locomotive apparatus in gymnasts. The difference in heigth was found (д 1 mm), measured with Martin's anthropometer in lying and upright positions (accuracy ± 0.5 mm) before and immediately after training [39, 40]. The characteristics of training load were registered: capacity Q (elements), intensity J (relative unit of measurement [1]), per cent of stroke load in total capacity of training U%. It was found that the locomotive apparatus of gymnasts can re­ act differently to the equal training load. 2 main types of reaction of the intervertebral fibrocartilage locomotive apparatus of gymnasts became evident: the positive and the zero type. In case of positive reaction, the value of the д 1 mm increases significantly relative to the initial position: 14.15 ± 0.64 mm before and 16.74 ± 1.05 mm after the training load (p < 0.05) by Student's criterion; in case of zero reaction there are no changes 10.79 ± 0.94 mm before and 10.69 ± 0.80 mm after the load. The analysis made possible the conclusion that during the train­ ing session, determination of difference in height д 1 is one of the possibiUties to dose individually the stroke load and to avoid in­ juries. Key words: locomotive apparatus; stroke load; competitive gym­ nasts. 186 Introduction The development of complicacy and originality of programs in competitive gymnastics evokes a constant growth of training loads. Loads in this kind of sport have the character of strength and speed and are monthly connected with strokes to the locomotive apparatus (LA). These are mainly jumps, dismounts, landings [12, 45, 47]. The impact load has an effect both on upper and lower limbs. Accordingly, the gymnast is repeatedly under the compression causing forces during 6—7 kouse Lours training, which exceed many times the sportsman's own weight Etwas established by Vain [41] that the main-load during the land­ ing influences on the ankle joint but the acceleration arisen in leg during the collision of lower limb and rigid surface is 5-10 g (acceler­ ation of gravity). Studies of american scientists [23] showed that high jumps in aer­ obic dance cause many injuries of LA as they evoke twice as big a vertical force on the knee-joint as low jumps. Kurys [20] has estab­ lished that the load on lower limbs in the first phase of back flip is 270-350 kg, the load to upper limbs during stay is 250-300 kg . The total load to the whole LA during the pushing off pirouettes is 700 kg. Many authors have established that intensity of training-loads cause big changes in LA of sportsmen, that lead to microinjuries. The latter, in turn, cause pathological phenomena [4, 7, 14, 24, 28, 32]. Bäk et al. [3], Hamel [15], Bashkirov [4, 5], Mironova et al. [25] direct attention to the fact that the weakest parts are the points where muscles are passing over to tendons and tendons are fixed on bone tissue. These are the parts of high tensions. In connection with that, the whole LA and its connective tissues deform under the influence of intensive impact loads. Chenegin [47], Zaikin et al. [45], Belyakova etal. [6] found out that after intensive training the foot of the gymnast is flattened. Results of that are disturbances of the restoring function of the arch of the foot. Great attention to the function of the arch of the foot in softening strokes and impacts was also showed by Lesgaft [21], who stvessed the consequence in mastering jumping exercises [22]. Researchers [10, 29, 34] showed that intensive loads of impact character cause early synostosis of knee-joint fissure, disturbances in normal feeding of gristle tissue, also lower resiliency of gristle tissue. Rokitjanski [31], Ehricht [11], Tager, Dyachenko [36], Raichin- shtein [30], Vital et al. [42], Stupakov, Oksagoyef [35], Yumanov [18] and others have shown that degenerative changes in intervertebral fibrocartilage of the spinal column are connected with impact loads to the spinal column. Burukhin [43], Naylor [26], Ehricht [11] have explored the func­ 187 tional condition of the intervertebral disk in the spinal column and have found that the nucleus pulpous is able to stand only small and medium loads. Big loads on the axle disturbe the metabolism of the nucleus pulpous. The collagen structure is changed to fibrous tissue, causing lower flexibility and disturbances of amortisation. The above given data affirm that intensive training loads of impact character cause abatement of amortisation of LA; the flexibility of LA disappears. Further intensification of training loads can cause injuries and degenerative changes of LA, that force sportsmen to leave sport and make them invalid [5, 8,25]. In connection with these data the most troublesome fact is that female competitive gymnasts specialize very early. The highest results are shown already at an age when the LA is physiologically not yet prepared for standing impact loads and it is extremelv flexible [5, 27, 33]. Researchers have stressed that forced training, drilling of talented children for getting quick results is impermissible. The level of the physical loads must not exceed the functional qualities of LA [13,25, 44,47]. But, as noted by Dembo [9], the level of permissible load is indi­ vidual and to determine its optimality is quite difficult. The above given material makes clear that determination of the function of connective tissues in LA (i.e. amortisation ability of LA) in competitive gymnasts and its connection with training load is actual. The aim of the present work was to control one of the possibilities to determine the reaction of connective tissues in the gymnast's LA to training loads of impact character. Subjects and methods The research work was carried out on the basis of Tallinn's Spe­ cialized Gymnastic School. 14 highly qualified female competitive gymnasts from age 9 to 14 took part in the research. Throughout some years the data of training loads had been peri­ odically registered: capacity Q (elements), intensity I (relative unit of measurement, Afonin, [1]), per cent of impact load in the whole capacity of training — U%, and anthropometrical indices: height (with Martins metal anthropometer) with ± 0.5 mm and weight with ± 0.1 kg accuracy. The index д 1 mm, which reflects indirectly the functional condition of connective tissue in LA, was determined [6, 39,40]. Every observation was usually carried out in 3 days. Before and immediately after the training the change in height of the gymnast was measured on a special stand in lying and standing positions д 1 mm (before the training) and д 1 mm (after the training). There was 188 also determined the arithmetical mean L mm of instability in height differences per gymnast during the whole day. On the ground of the arithmetical mean in height differences we got the general estimate on the functional condition of LA per day, on the ground of д 1 mm dynamics we explored the shifts, which took place in the functional condition of connective tissues in LA under the influence of training load. As is generally known, the enlargement of curves in the spinal column and diminishing of thickness of its intervertebral fibrocartilage are the negative indices of supernumerary physical loads and cause residue deformations [16,37,38]. In this case д 1 mm decreases. The received results were treated statistically. Results and discussion The analysis was carried out on the ground of data gathered in 3 years. All girls were divided into 2 groups. Criterion for differen­ tiation was the minimal index of arithmetical mean L mm, which was 6.89 ± 3.94 mm from the variation row. The latter was composed of arithmetical means' indices of height-differences L mm per gymnast during the whole experimental period. Group A consisted of 6 gymnasts (mean age 10.8, height 1344.1 ± 70.47 mm, weight 29.81 ± 1.26 kg, whose L mm arithmetical mean excuded the minimum value twice: 15.29 ± 0.81 mm. Group В consisted of 8 gymnasts (mean age 12.1, height 1364.8 ± 59.12 mm, weight 31.89 ± 1.65 kg), whose L mm arithmetical mean excuded the minimum value 1.6 times: 11.06 ± 0.69 mm. Comparing arithmetical means of the received results by Student's criterion gave the following results: Afterwards the indices of height differences were compared before д 1 mm and after д I mm the training load: group A before training 14.15 ± 0.64 mm, group В before training 10.79 ± 0.94 mm; group A after training 16.74 ± 1.05 mm, group В 10.69 ± 0.81 mm. Differ­ ences between the groups in the above given indices are statistically significant (p < 0.01). (Fig. 1). In training load indices — Q, I, Uimportant differences. Neither were there significant differences in anthropometrical indices of both groups — height, weight. Comparison of indices of arithmetical means д 1 mm inside groups before and after training load: in group A the differences in д 1 mm during the training are statistically significant (p < 0.05). In group В no essential differences were found in д 1 mm before and д 1 mm after the training load. We can assume that in group A the height differences during the day L mm (i.e. index of arithmetical means during the whole research) 189 25 Influence oftraining load on the functional condition of locomotive apparatus in gymnasts: intergroups dynamics ( L and д!, mean ± SD). 1 before training A 1 after training * p < 0 , 0 0 1 1 p < 0,01 1. group |Ш SD 1 Fig. 1. Differences between the groups in L mm index are statistically signif­ icant (p < 0.001). was 15.29 ± 0.81 mm. It means that LA functions normally and the reaction of connective tissues to loads is satisfactory. This is indicated by the statistically significant increase of д 1 mm after the training load. (Fig. 2). The situation in group В is different. The index of height differ­ ences during the day L mm (i.e. arithmetical mean during the whole research) was 11.06 ± 0.69 mm. Therefore the reaction of LA to training load is not satisfactory, because no positive shift was found in its functional condition after the training. This is indicated by the lack of statistically essential difference between arithmetical means д 1 mm before and immediately after the training load. (Fig. 2). It is evident that the amortisation function of LA is disturbed in group B, i.e. LA cannot soften strokes. In that case the impact wave reaches almost without obstacles the above-situated body segment at the very moment of collision between metatarsus and rigid surface [2, 17, 46] expressing negative influence on ligaments, joints, and intervertebral fibrocartilage of the spinal column. This creates real danger of microinjuries, further also of severe injuries. The previous analysis showed that the arithmetical mean of unit L mm has correlation with striking-load U Correlation analysis inside groups made evident that there is con­ nection between striking-load Üof group A gymnasts is durable to the chosen training load i.e. the latter does not significantly influ- 190 К) I i 1 • m 00 ; С? М 'с' р ö О i l l I -н о гx»i- o-H й ' VnC V 1 — ЧО о а 1-1 чxоh xj-U Ьр on о ö о -н -Hn о Or- V О CL Q се 00 OЧОn -H о Ö О О 1On -н о сvп О ЧО V В i Он 2 oСПn 0р0 гН сп 00 -гн- -jnн 1 oЧnО КЧО $ Р "mt CS > I—I vo о о Tоt S-E -н -н 'ьф, й S CS 3 А ö о Л Otnn чо ае Оси -tj- ов Sи O -и in сп W tЧnО eспs CS CS I •^t Cj ö otnn Э.а -H -н яо 5 ̂ xxth" ^чdо-СП сп t—h т—) о <ЧОn tvnq яа ,£Р ас -0t0i -oн О n eOns ст-пН poo 00 Оьр и cn ö ^<£ л >ч>> 0 -H0 -н öт-ч CS оtn В cs so о о 2 40 V й и & и а, н С и С 25* Influence of training load on the functional condition of locomotive apparatus in gymnasts:intragroups dynamics (J, mean ±SD). 1st. group 2nd. group * p < 0,05 С] before m after 11 SD 1 Fig. 2. ence the unit'characterizing the functional condition of LA in these sportswomen. Correlation between impact load and L mm in group В was 0.24 (p < 0.05). Consequently, the impact load influences essentially the LA of group В gymnasts. Therefore reaction to impact load was different. In group A (mean age 10.8 ± 3.1) positive shifts were found in reactions of connective tissues in LA to impact load i.e. the positive type of reaction was found. Arithmetical mean of д 1 mm shows significant enlargement after the training compared with the initial position, which speaks about the adequacy of training load to the function of connective tissues in LA in gymnasts of group A. In group В (mean age 12.1 ± 0.48) the reaction of connective tis­ sues in LA to training load lacked statistically essential shifts. It is indicated by the lack of statistically essential differences in arithmeti­ cal means of 1 mm before and after training. Connective tissues of LA showed zero-type reaction to the training load. This fact gives us rea­ son to assert that the amortisation function of LA has been disturbed. The given training load is not adequate to the functional condition of connective tissues in LA in this research group. Real danger for injuries of LA results from here. The received data coincides with scientific literature. Simakov [34] has shown that LA of 12-13 years old children is unable to stand intensive training loads of impact character. Loads of this kind cause disharmony between 192 the intensive development of muscles and skeleton. Fyodorova [13] analyzed reasons of injuries in gymnasts and made a conclusion that the first culmination point of injuries for female competitive gymnasts is at about age 12. Our conclusions were verified by the fact that there were no serious injuries of LA in group A. In group В there were 2 serious injuries of achilles tendon (tendon's rupture and rupture of connective tissues of achilles in germination zone), also serious injuries of foot and knee- joint Conclusion The present study allows to declare that difference in the height of gymnasts, measured in lying and upright position as the parameter д 1 mm before and after the training, is an informative showing. On the ground of this it is possible to appraise indirectly the reaction of the gymnast's connective tissues in locomotive apparatus to the training load. The dynamics of parameter д I mm allows to explore shifts in the functional state of connective tissues of the locomotive apparatus. It became evident that the zero type of reaction informs about distur­ bances of amortisation capacity in the locomotive apparatus. This is closely connected to risk of injuries. Female competitive gymnastics are characterized by big impact load and that causes notable individual differences in the reaction of the locomotive apparatus. During the training session the determi­ nation of д 1 mm is one of the possibilities to dose individually the stroke load and to avoid injuries. REFERENCES 1. Afonin, V. N. Pedagogic estimation of training load's intensity in gym­ nasts. — Gymnastics, 1976, Part. 1,13-15. 2. Aruin, A. S., Zatsiorski, V. M. Ergonomie biomechanics of walking and running. Moscow, 1989,251 p. 3. Bäk, K., Kalms, S. В., Giesen, S., Jorgensen, U. Epidemiology of injuries in gymnastics. — Scand. J. Med. Science in Sports, 1994, 4,148-154. 4. Baskirov, V. E Origin and treatment of injuries in sportsmen. Moscow, 1981,224 p. 5. Baskirov, V. E Complex rehabilitation of sportsmen after injuries of loco­ motive apparatus. Moscow, 1984,240 p. 6. Belyakova, N. Т., Kuznetsova, L. J., Kuznetsov, M. M. Influence of inten­ sive loads on locomotive apparatus in young gymnasts. — Gymnastics, 1974, Part.2,14-15. 193 7. Сагек, Е J., Fiusiieh, R. M. Stress Fracture of the Distal Radius. (Not Just a Risk for Elite Gymnasts). — The Physician and Sportmedicine. 1992, 20,115-118. 8. Denser, E. Die Gesundheit des Sportiers. Econ Verlag, Düsseldorf—Wien 1977. 9. Dembo, A. G. Causes and prophylaxis of health condition's deflections in sportsmen. Moscow, 1981,120 p. 10. Dobrovolski, V K. Prophylaxis of injuries,its pathologic conditions and deseases in sports. Moscow, 1967,208 p. 11. Ehricht, H.-G. Die Wirbelsäule in der Sportmedizin. Johann Ambrosius Barth. Leipzig 1978,28-40. 12. Fyodorova, Т. V. Training and competition's load of female young gymnasts in they ear cycle of training. — Theory and Practice of Physical Education. Moscow, 1991, 7,54-57. 13. Fyodorova, Т. V Injuries and deseases of locomotive apparatus in gym­ nasts. — Theory and Practice of Physical Education. Moscow,1 991,5,23- 25. 14. Franke, К. Sport traumatology. Moscow: Medicine, 1981,352 p. 15. Hamel, R. Achilles Tendon Ruptures. — The Physician and Sportmedicine. 1992, 20,189-200j 16. Huang, H. K,, Sadley R. S. Application of the classical contact theory to deformation of the skeletal joints. — Intern. Ser. Sport Sei., 1974, 1 Biomechanics, 4,399-408. 17. Yumashev, G. S. Osteochondrosis of spine. Moscow: Medicine, 1984,382p. 18. Yumanov, N. A. Extension-prophylaxis of impact-inertional influences and static loads on the spine. — Theory and Practice of Physical Education. Moscow, 1991,2,51-53. 19. Kums, T. The influence of stroke loads on the functional state of loco­ motive apparatus in gymnasts.Int.conf.Somatotype of Children II, Tartu, Estonia, June,15-18,1994,29-30. 20. Kurys, V. N. Complex method of technique investigation as a way of im­ provement of training process to complicated acrobatic jumps. — Gym­ nastics, Moscow, 1974, Part. 2,9-12. 21. Lesgaft, E F. About importance of strikes and shaking in the organism of human and animals. The References of St.Petersburg's Biological Labo­ ratory, 1898, Part. 4,41-48. 22. Lesgaft, R F. Guidance on the physical education of schoolboys. Collected Pedagogic articles. Moscow, 1952,74. 23. Michaud, T. J., Rodriguez-Zavas, J., Armstrong, G., Hartnig, M, Ground reaction forces in high impact and low impact aerobic dance. — J.Sports Med. Phys Fitness, 1993, 33,359-366. 24. Mironova, Z. S., Morozova, E. M. Sport traumatology. Moscow, 1976, 172 p. 25. Mironova, Z. S., Merkulova, R. J., Bogutskaya, E. P., Badnin, J. A. Overstrain of locomotive apparatus in sportsmen. Moscow, 1982, 95 p. 26. Naylor, A. The biophysical and biofchemical aspects of intervertebral disc herniation and degeneration. — Ann. Roy. Coll. Surg. Engl., 1962,31,91. 27. Nigg, В. M. Kinder im Leistungssport. Leipzig, 1982,60-65. 28. Nikityuk, B. A., Kogan, B. J. Adaptation of skeleton in sportsmen. Kiyev: Health Publ., 1980, 32. 194 29. Nikityuk, В. A. Some contradiction of modern sport morphology and these settlement in the light of P. F. Lesgaft ideas. — Theory and Practice of Physical Education, 1987, 8,43-45. 30. Raichmshtein, B. Ch. Intradisc pressure as index of functional condition of lumbal intervertebral discs. Author's Abstract of doctor dissertation. Moscow, 1975, 51p. 31. Rokityanski, B. J. Injuries and Orthopaedic Diseases in Physical Educa­ tion and Sports. Moscow: Medicine, 1964,236p. 32. Seeder, J. H. Sport Traumatology. Tartu, 1980, 82p. 33. Simakov, У.V . Collected articles: Medical and pedagogic aspects of young sportsmen's training. Smolensk, 1989,76. 34. Simakov, V. V., Karmenov, B. A. Adaptation and prophylaxis of injuries of osseus-articulate apparatus in the mechanical overloads. — Theory and Practice of Physical Education. Moscow, 1991,1,32-35. 35. Stupakov, G. E, Oksagoyef, A. A. Spine reaction on longitudinal load­ ing. — Modern problems of biomechanics. Riga, 1989. Part 6,19-46. 36. Tager, I. L., Dyachenko, V L. Roentgen Diagnostics of Spine Injuries. Moscow: Medicine, 1971. 344 p. 37. Tittel, K. Zur Ätiologie, Morphologie und Prophylaxe der Sportverlet­ zungen und -Schäden am Bewegungsapparat. — Z. ärztl. Fortb. 1962,1, 52. 38. Tittel, K. The possibilities of spine loads in the point of view of functional anatomy. — Biology, Biomechanics, Biochemistry, Medicine, Physiology (Ш direction). Moscow, 1980, p.325. 39. Vain, A. A. Dynamics of residual deformations of the locomotive dynamics of residual deformation of the locomotive apparatus in young gymnasts. — Theses of XXI republic conference on Physical Education and Sport. Tartu, 1981, p.11-15. 40. Vain, A.A. Diagnostics of locomotive apparatus of sportsman. — Modern problems of biomechanics. Riga, 1986, Part 3, 85-96. 41. Vain, A. A. Research of mechanical impedance of human body during the collision of locomotive apparatus and rigid surface. Abstracts of the I Ail-Union Scientific Conference in Biomechanics. Kiyev, 1974, Part 2, 20. 42. Vital, E. A., Yamishkevich, A. F., Danos, Y. A. Characteristics of human spine durability by impact loads. — Modern problems of biomechanics. Riga, 1986, Part 6,47-62. 43. Tsivyan, Y. L., Burukhin, A. L. Pathology of the degenerative interverte­ bral disc. Novosibirsk: Science, 1988,142 p. 44. Zaglada, V. E., TYeshchyova, O. L. Training of highly skilled sportsmen. — Gymnastics, 1982, Part 1,29-34. 45. Zaikin, V. G., Saveljev, V. S., Andrianov, N. Y. Possibilities of jumping load's improvement by means of the change of acrobatic track's charac­ teristics. — Gymnastics, 1987, 49-51. 46. Zatsiorski, V. M., Sazonov, V. P. Biomechanics bases of injuries' prophy­ laxis in the spine's lumbar region by physical exercises. — Theory and Practice of Physical Education. Moscow, 1985, 7,33-41. 47. Chenegin, V. M. Methods of control of the training loads in competitive gymnastics. — Gymnastics, 1987, 8-12.