Effects of Maturation Stage on Physical Fitness in Youth Male Team Sports Players After Plyometric Training: A Systematic Review and Meta-Analysis

Background： A comprehensive summary of the effects of plyometric training （PT） on multiple physical fitness indicators in youth athletes at different maturation stages, as well as on a broader range of sports, has not yet been conducted.This study aims to comprehensively summarize the effects of plyometric training on multiple physical fitness indicators of young male team athletes at different stages of maturity. Methods： This systematic review and meta-analysis followed PRISMA 2020 guidelines. Three databases (PubMed, Web of Science, SCOPUS) were searched. Study eligibility was rated using the PICOS method, and methodological quality was assessed with the PEDro scale. A random-effects model calculated the meta-analysis, reporting Hedge's g effect sizes (ES) with 95% confidence intervals (95% CI). Statistical significance was set at p ≤ 0.05. Egger’s test assessed bias, with the trim and fill method applied if necessary. Subgroup analyses and meta-regression calculations of training variables were performed. Result ：A total of 31 studies were included, involving 717 soccer players, 146 basketball players, 54 handball players, and 110 volleyball players. Compared to the control group, PT improved the following metrics across all age groups combined: Countermovement jump (CMJ) height (ES = 0.761), Standing long jump (SLJ) distance (ES = 0.572), ≤10-m linear sprint time (ES = -0.709), >10-m linear sprint time (ES = -0.488), and change-of-direction (COD) time (ES = -0.896).In the 10 to 12.99 years age group (PRE), PT improved CMJ height (ES = 0.73), SLJ distance (ES = 0.441), ≤10-m linear sprint time (ES = -0.431), >10-m linear sprint time (ES = -0.307), and COD time (ES = -0.783). In the 13 to 15.99 years age group (MID), PT improved CMJ height (ES = 0.523), >10-m linear sprint time (ES = -0.37), and COD time (ES = -0.635). In the 16 to 18 years age group (POST), PT improved CMJ height (ES = 1.053), SLJ distance (ES = 1.329), ≤10-m linear sprint time (ES = -1.81), >10-m linear sprint time (ES = -1.18), and COD time (ES = -1.665).There were no significant differences in adaptations for maximal strength in all groups, SLJ distance and ≤10 m linear sprint time in the MID group (all p > 0.05).Meta-regression showed that training variables could not predict the impact of PT on physical fitness. Subgroup analysis showed that when the total number of training sessions was ≥16 (ES = 1.061), there was a significantly greater improvement in CMJ height compared to fewer than 16 training sessions (ES = 0.36) (p = 0.002). Conclusion： Compared to the control group, PT can improve CMJ height, SLJ distance, ≤10-m linear sprint time, >10-m linear sprint time, and COD time in youth male team sports players across all age groups. However, PT does not improve maximal strength. The trend of improvement appears to be best during the late adolescence stage. In contrast, during mid-adolescence, SLJ distance and ≤10-m linear sprint time did not improve, and the improvements in CMJ height and COD time seem to be the least pronounced during this stage.