Modeling growth and maturation changes in peak oxygen uptake in 11-13 yr olds

The influence of gender, growth, and maturation on peak O-2 consumption. (( V)over dot O-2peak) in 11-13 yr olds were examined by using multilevel regr ession modeling. Subjects were 119 boys and 115 girls, aged. 11.2 +/- 0.4 ( SD) yr at the onset of the study. Sexual maturation was classified accordin g to Tanner's indexes of pubic hair. (V)over dot O-2peak was determined ann ually for 3 yr. The initial model identified body mass and stature as signi ficant explanatory variables, with an additional positive effect for age an d incremental was apparent with lower values for girls, and an age-by-gende r interaction indicated a progressive divergence in boys' and girls' (V)ove r dot O-2peak. Subsequent incorporation of the sum of two skinfold thicknes ses into the model negated stature effects, reduced the gender term, and ex plained much of the observed maturity effects. The body mass exponent almos t doubled, but the age-by-gender interaction term was consistent with the i nitial model.