he purpose of this study was to analyze the influence of
body fat and somatotype on explosive strength and aerobic
capacity trainability in the prepubertal growth spurt, marked by
rapid changes in body size, shape, and composition, all of which
are sexually dimorphic. One hundred twenty-five healthy children
(58 boys, 67 girls), aged 10–11 years (10.8 6 0.4 years), who
were self-assessed in Tanner stages 1–2, were randomly
assigned into 2 experimental groups to train twice a week for
8 weeks: strength training group (19 boys, 22 girls), endurance
training group (21 boys, 24 girls), and a control group (18 boys,
21 girls). Evaluation of body fat was carried out using the method
described by Slaughter. Somatotype was computed according
to the Heath-Carter method. Increased endomorphy reduced the
likelihood of vertical jump height improvement (odds ratio [OR],
0.10; 95% confidence interval [CI], 0.01–0.85), increased
mesomorphy (OR, 6.15; 95% CI, 1.52–24.88) and ectomorphy
(OR, 6.52; 95% CI, 1.71–24.91) increased the likelihood of
sprint performance, and increased ectomorphy (OR, 3.84;
95% CI, 1.20–12.27) increased the likelihood of aerobic fitness
gains. Sex did not affect the training-induced changes in strength
or aerobic fitness. These data suggest that somatotype has
an effect on explosive strength and aerobic capacity trainability,
which should not be disregarded. The effect of adiposity
on explosive strength, musculoskeletal magnitude on running
speed, and relative linearity on running speed and aerobic
capacity seem to be crucial factors related to training-induced
gains in prepubescent boys and girls.
