Plyometric Training in Prepubertal Soccer Players: Is It Really Effective for Soccer Performance?

Background/Objectives: Plyometric training is a method of increasing soccer performance which leverages the muscle stretch-shortening cycle. This study aimed to evaluate the safety and effectiveness of plyometric training in prepubertal soccer players. Methods: Twenty-three young athletes (age 9.4 ± 0.3 years) from an elite club, training three times per week, were enrolled. During one of the weekly training sessions, twelve players formed the experimental group (PLYO), incorporating a 45 min plyometric training component into their routine, while the control group (CON), consisting of eleven players continued with their usual training program. At baseline and after 12 weeks, anthropometric parameters, flexibility, lower limb strength, and agility were assessed. Results: At baseline, no differences were observed between the two groups in anthropometric or physical performance parameters. No injuries occurred during the study. After 12 weeks, both groups showed significant growth and performance improvements. However, the PLYO showed a significantly greater increase in lower limb strength (Δ + 10.7%) compared to the CON (Δ + 6.0%). Conversely, although not statistically significant, agility improvements were greater in the CON (Δ + 12.4%) than in the PLYO (Δ + 8.6%). Conclusions: Plyometric training appears to be a safe and effective method for enhancing lower limb strength in prepubertal athletes. However, this strength gain did not directly translate into greater agility, which may benefit more from sport-specific training during this developmental stage.