Longitudinal changes in young people's short-term power output.

Abstract

The influences of age, body size, skin-fold thickness, gender, and maturation on the short-term power output of young people were examined using multilevel modelling. Subjects were 97 boys and 100 girls, aged 12.2 +/- 0.4 yr at the onset of the study. Sexual maturity was classified according to Tanner's indices of pubic hair. Peak power (PP) and mean power (MP) were determined on two occasions 1 yr apart using the Wingate Anaerobic Test (WAnT). The data were analyzed using multilevel regression modelling. Initial models identified body mass and stature as significant explanatory variables with an additional positive effect of age, which was smaller for girls' MP. A significant gender difference was apparent for both power indices with girls achieving lower values than boys. A significant incremental effect of later maturity (stages 4 and 5 for pubic hair development) was identified for MP only. Subsequent incorporation of sum of two skin-fold thicknesses into the model yielded significant negative parameter estimates for PP and MP and negated both the stature effects and the maturation influence upon MP. There are gender differences in the longitudinal growth of performance on the WanT. Regardless of gender differences, body mass and skin-fold thicknesses appear to be the best anthropometric predictors of WAnT determined PP and MP in young people.