Influences of body-size variables on age-related increases in isokinetic peak torque in young wrestlers

The purposes of the present study were to determine the patterns of age-related changes in 1) height (HT), body weight (BW), fat-free weight (FFW), and absolute isokinetic peak torque (PT); and 2) isokinetic PT covaried separately for HT, BW, FFW, and HT and BW combined in young wrestlers. One hundred twenty-five male wrestlers (mean age ± SD = 14.3 ± 2.4 yr; range = 11.1-18.2 yr) volunteered to perform concentric, isokinetic leg extension and flexion at 180°·s^-1 on a Cybex II dynamometer to measure PT as well as underwater weighing to determine FFW. The polynomial regression analyses indicated there were significant quadratic increases across age for HT (R² = 0.62), BW (R² = 0.56), and FFW (R² = 0.47). For leg extension, there were significant increases across age for absolute PT (quadratic, R² = 0.66), PT covaried for HT (linear, r² = 0.10), PT covaried for BW (linear, r² = 0.12), PT covaried for FFW (quadratic, R² = 0.32), and PT covaried for HT and BW combined (quadratic, R² = 0.11). For leg flexion, there were significant increases across age for absolute PT (linear, r² = 0.59), PT covaried for HT (linear, r² = 0.07), PT covaried for BW (linear, r² = 0.08), PT covaried for FFW (quadratic, R² = 0.23), and PT covaried for BW and HT combined (linear, r² = 0.03). The results of this study indicated that age-related increases in leg-extension and flexion PT for the current sample of young wrestlers could not be accounted for by changes in HT, BW, FFW, or HT and BW combined. These findings suggested that neural maturation may contribute to increases in leg strength across age in young wrestlers.