Maturity Status Does Not Exert Effects on Aerobic Fitness in Soccer Players After Appropriate Normalization for Body Size

The present study investigated the effects of pubertal status on peak oxygen uptake (VO2peak), respiratory compensation point (RCP), and ventilatory threshold (VT) in young soccer players using different body size descriptors. Seventy-nine soccer players (14 prepubescent, 38 pubescent and 27 postpubescent) participated in this study. A maximal exercise test was performed to determine the VO2peak, RCP, and VT. Ultrasonography was used to measure lower limb muscle volume (LLMV). LLMV (mL(-b)) was rated as the most effective body size descriptor to normalize VO2peak (mLO(2).mL-0.43.min(-1)), RCP (mLO(2).mL(-0.48).min(-1)), and VT (mLO(2).mL(-0.40).min(-1)). The values of VO2peak, RCP, and VT relative to allometric exponents derived by LLMV were similar among groups (p > .05; 0.025 < eta(2) < 0.059) when the effect of chronological age was controlled. Allometric VO2peak, RCP, and VT values were: 100.1 +/- 7.9, 107.5 +/- 9.6, and 108.0 +/- 10.3 mLO(2).mL(-0.43).min(-1); 51.8 +/- 5.3, 54.8 +/- 4.7, and 57.3 +/- 5.8 mLO(2).mL(-0.48).min(-1); and 75.7 +/- 7.1, 79.4 +/- 7.0, and 80.9 +/- 8.3 mLO(2).mL(-0.40).min(-1) for prepubertal, pubertal, and postpubertal groups, respectively. Maturity status showed no positive effect on VO2peak, RCP, and VT when the data were properly normalized by LLMV in young soccer players. Allometric normalization using muscle volume as a body size descriptor should be used to compare aerobic fitness between soccer players heterogeneous in chronological age, maturity status, and body size.