Einfluß des Sports auf die Entwicklung von 10-11jährigen Knaben - I. Körperzusammensetzung, anthropometrische Parameter und Kreatininausscheidung

Abstract

We compared body composition (measured by total-body water determination), skinfolds, body circumferences and diameters and the muscle arm area of 10 to 11-year-old boys (n = 21) at the beginning and the end of a 9-months training period (track-and field athletics) with data obtained in 12 control subjects of corresponding ages. Urinary creatinine excretion was measured as a parameter of muscle mass at the end of the training period. Boys engaged in training gained (mean: + 2,6 kg) significantly less (p less than 0,05) weight than controls (mean: + 3,9 kg). Fat-free mass (FFM) as percentage of weight significantly increased in boys engaged in training (mean: + 1,8%; p less than 0,005) at the expense of fat whereas in controls (mean: + 0,6%; p: n.s.) there was no significant change. Decreasing skinfold thickness in boys engaged in training indicated reduction of subcutaneous fat. In controls, subcutaneous fat increased at the trunk and decreased at the periphery. Regression analysis indicated that changes of triceps skinfold thickness did not reflect changes in body fat content (r = 0.30; p: n.s.). A significant relation was established between changes of the subcapular skinfold thickness (r = 0,46; p less than 0,005) and of the sum of 5 skinfolds on the one hand (r = 0,51; p less than 0,005) and the changes of body fat content on the other hand. High standard deviations from the regression lines, however, indicated that accurate prediction of changes in body fat content was not possible in an individual subject.(ABSTRACT TRUNCATED AT 250 WORDS)