Purpose Plyometric jump training (PJT) is an effective means of developing speed, strength, and neuromuscular parameters in youth athletes. However, the effect of PJT on performance outcomes as a function of biological maturation remains unclear. Methods Employing a 12-week training intervention, 37 youth male soccer players aged 10–18 years were stratified by biological maturity using the Mirwald equation (pre-PHV versus post-PHV) and subsequently randomized to a PJT group (pre-PHV: n = 10, post-PHV: n = 10) or a control group (pre-PHV: n = 7, post-PHV: n = 10). The PJT group trained twice per week, with sessions based on multidirectional and short ground contact time exercises. The following performance outcomes were assessed: 20-m sprint, L-run, broad jump, unilateral triple jump, countermovement jump, reactive strength index, and relative leg stiffness. A three-way ANOVA for repeated measures was used for statistical analysis. Results No significant time × intervention × maturity interaction was detected for any variable (all p ≥ 0.21). The 20-m sprint improved significantly in both PJT groups ( p ≤ 0.002), whereas the control group improved only in pre-PHV ( p = 0.038). Performance in the L-run improved across all groups ( p ≤ 0.003), with no specific intervention effect. Broad jump improved only following PJT ( p = 0.001). Unilateral triple jump showed significant gains in both PJT groups ( p ≤ 0.032). Relative leg stiffness increased in both PJT groups ( p ≤ 0.003), while it decreased significantly in the post-PHV control group ( p = 0.013) and remained unchanged in the pre-PHV control group ( p = 0.68). Conclusions PJT appears to be a suitable and effective method for developing speed, explosive power and neuromuscular performance in youth male soccer players both before and after PHV. However, our results indicate that the role of PJT in influencing physical qualities during adolescence may be different.
Holík et al. (Wed,) studied this question.