Timing is everything: the age-related impact of plyometric training on lower limb explosive strength in male adolescents and its general effectiveness in female adolescents

This study investigates the impact of plyometric training on age-related lower limb explosive strength in male adolescents and its effectiveness in female adolescents. A thorough search was conducted across five databases from their inception until September 20, 2024. Study quality was assessed using the Cochrane Risk Assessment Tool, and data analysis was performed with Stata 15 software. Plyometric training positively affected countermovement jump (CMJ) (MD = 2.90 cm, 95% CI (2.35, 3.45)), squat jump (SJ) (MD = 2.57 cm, 95% CI (1.69, 3.44)), and 20-m sprint performance (MD = − 0.09 s, 95% CI (− 0.14, − 0.05)). Subgroup analysis revealed varying improvements across age stages. In CMJ, the early adolescence (EA) group (MD = 2.57 cm, 95% CI (1.74, 3.40)), mid-adolescence (MA) group (MD = 3.04 cm, 95% CI (2.30, 3.79)), and post-adolescence (PA) group (MD = 3.89 cm, 95% CI (1.96, 5.81)) showed progressive enhancement. The MA group exhibited superior improvements in SJ (MD = 3.78 cm, 95% CI (2.19, 5.36)) and 20-m sprint (MD = − 0.11 s, 95% CI (− 0.18, − 0.05)) compared to the EA group (SJ: MD = 2.10 cm, 95% CI (1.43, 2.77); sprint: MD = − 0.06 s, 95% CI (− 0.11, − 0.01)). The PA group showed no significant improvements (SJ: MD = 1.31 cm, 95% CI (− 1.05, 3.67); sprint: MD = − 0.27 s, 95% CI (− 0.61, 0.07)). For female adolescents, plyometric training effectively improved CMJ (MD = 2.55 cm, 95% CI (1.43, 3.66)), SJ (MD = 2.33 cm, 95% CI (1.36, 3.31)), and 20-m sprint performance (MD = − 0.22 s, 95% CI (− 0.33, − 0.12)). Plyometric training significantly enhances lower limb explosive strength in both male and female adolescents, with age-dependent effects for male adolescents. The greatest improvement in CMJ was observed in the PA stage, followed by the MA stage, while the EA stage showed the least. The MA stage exhibited the best improvements in SJ and sprint performance. The study has been registered in the International Prospective Register of Systematic Reviews (PROSPERO: CRD42023406914).