Physiological evaluation of elite young soccer players - A longitudinal study

The present study aimed to describe, longitudinally, the physiological characteristics of circa-pubertal soccer players. The sample was divided into 8 prepubertal (PP), and 6 midpubertal (MP) subjects according to the level of sexual maturity. Participants were assessed initially (T1) and after 2 years of regular training (T2). Peak oxygen uptake (<(V)over dot>O-2peak) and ventilatory threshold (Tvent), were used as indicators of cardiorespiratory fitness. Maximal muscle peak power (Wp) was assessed by a squatting jump (SJ) and a countermovement jump (CJ), performed on a force platform. No significant differences were found between the two groups in <(V)over dot>O-2peak at T1 (60.1+/-5.1 [PP] and 65.0+/-7.2 [MP] ml . kg(-1) . min(-1)), <(V)over dot>O-2 at Tvent corresponded to about the 80% of <(V)over dot>O-2peak in both groups. Wp (W . kg(-1)) was significantly higher in MP only in SJ (p<0.05). At the second evaluation (T2) only PP subjects showed a significant increment in all variables. This study showed the high level of physical fitness of these athletes, and confirms the importance of growth and sexual maturation for developing physical fitness in circa-pubertal subjects. Further research is needed to verify these findings, especially including a control group of untrained children.