Effects of plyometric training on match running performance in elite U20 male soccer players at moderate altitude

The effectiveness of plyometric training for improving isolated physical performance in soccer players is well established; however, its transfer to match running performance, particularly under chronic moderate-altitude conditions (~ 2000 m), remains unclear. This study examined whether supplementing regular soccer training with a structured plyometric training programme would enhance friendly match running performance in elite U20 male soccer players training at moderate altitude. Eighteen elite academy players completed a 16-week quasi-experimental, non-randomized, sequential within-subject intervention consisting of two consecutive 8-week training phases: regular soccer training only (control) followed by regular training supplemented with plyometric training (experimental). Match running performance was assessed during friendly matches using 10-Hz global positioning system technology (Catapult Sports, Australia) before the intervention, after the control phase, and after the plyometric training phase. Distance per minute (DPM), top speed (TS), high-speed running distance (HSR), sprint distance (SD), and explosive accelerations (EA) and decelerations (ED) were analyzed using generalized linear mixed models to account for repeated match observations within players. The fixed sequential design should be considered when interpreting the findings, as potential time-related and seasonal influences cannot be fully excluded. Following the regular soccer training phase, trivial or unclear changes were observed in DPM (ES; ±95%CL: 0.02 ± 0.19), HSR (0.13 ± 0.43), SD (0.01 ± 0.55), EA (0.03 ± 0.34), and ED (0.13 ± 0.37), whereas TS showed a substantial increase (0.63 ± 0.12). Following the phase that included additional plyometric training, substantial increases were observed in DPM (1.66 ± 0.19), TS (1.66 ± 0.12), HSR (1.18 ± 0.40), SD (1.39 ± 0.51), EA (1.03 ± 0.33), and ED (1.15 ± 0.38). The findings indicate that adding plyometric training to regular soccer training may provide an additional stimulus associated with enhanced match running performance in elite youth soccer players, even under long-term moderate-altitude conditions. However, the results should be interpreted cautiously given the non-randomized sequential design.