Comparison of plyometric repeated sprint and plyometric aerobic training on physical performance in youth soccer players.

High-intensity interval training (HIIT) and repeated-sprint sets (RSS) are established conditioning methods in soccer, yet their integration with plyometric training among highly trained youth soccer players remains underexplored. This study investigated the effects of an 8-week program combining plyometric training with either RSS (PLYO-RSS) or HIIT (PLYO-HIIT) on physical fitness in young soccer players. Twenty-nine male players (14-15 years) were randomly assigned to PLYO-RSS (n = 14) or PLYO-HIIT (n = 15). Both interventions lasted 20 minutes per session and replaced part of regular soccer training. Physical fitness assessments included countermovement jump (CMJ), 15-s repeated vertical jumps (15''RJ), five-jump test (5JT), 10 m and 30 m sprint, maximal aerobic speed (MAS), VO2max, and repeated sprint performance (total sprint time, best sprint, fatigue index). Physiological markers (lactate, rating of perceived exertion, and HRmax) were also monitored. Significant improvements over time were observed in muscle power, sprint speed, aerobic capacity, and repeated-sprint ability (p ≤ 0.001; η²p = 0.339-0.489). However, no main effects or group × time interaction effects were observed, indicating no evidence of differential responses between the two training modes. In conclusion, integrating plyometric training with either RSS or HIIT effectively enhances physical fitness in highly trained youth soccer players, offering flexible options for training prescription.