Short-Term Effects of Plyometric Training and Subsequent Detraining on Sprint Performance, Change-of-Direction Ability and Muscle Size-Related Changes in Prepubertal Boys

Background: Plyometric training is widely used to enhance explosive performance in youth athletes, yet limited evidence exists regarding the persistence of neuromuscular and morphological adaptations after training cessation in prepubertal populations. Objective: This study examined the effects of an 8-week plyometric training program on sprint performance, change-of-direction (COD) ability, and muscle size-related changes, and evaluated the retention of these adaptations following a 4-week detraining period in prepubertal basketball players. Methods: Twenty-eight prepubertal boys were allocated to either a plyometric training group or a control group. Sprint performance (5, 10, and 20 m) and COD ability were assessed, and muscle size-related changes were evaluated through measurements of muscle volume and cross-sectional area (CSA) of the thigh and calf. Assessments were conducted at baseline, after the intervention, and following the detraining period. Results: The plyometric group demonstrated significant improvements in sprint and COD performance and increases in muscle volume and CSA of the mid-thigh and calf (p ≤ 0.05). The control group showed modest improvements in sprint performance and muscle volume, likely reflecting normal growth and regular basketball participation. After 4 weeks of detraining, sprint and COD performance and muscle volume in the plyometric group declined to levels comparable with the control group, whereas CSA of the mid-thigh and calf remained elevated. Conclusions: These findings indicate that short-term plyometric training improves explosive performance and induces structural adaptations in prepubertal basketball players, although continued training stimuli appear necessary to maintain most performance-related gains.