Effects of Blood-Flow Restriction During Body-Weight Semi-Squats on Post-Conditioning Drop-Jump Performance in Adolescent Female Volleyball Players

This study investigated whether body-weight semi-squats (BWSSs) performed under blood-flow restriction (BFR) conditions were associated with higher post-conditioning drop-jump performance compared with the sham condition in adolescent female volleyball players. Thirteen players completed two experimental conditions (BFR and sham) in a randomized, counterbalanced crossover design. A pre-conditioning baseline jump assessment was not included. The BFR condition consisted of three sets of 16 repetitions with 80% of arterial occlusion pressure (AOP), whereas the sham condition was performed at 20% AOP. In each condition, participants performed one drop jump at 3, 6, 9, 12 and 15 min after the activation protocol. Jump height, impulse, reactive strength index (RSI) and power-related variables were analyzed using repeated-measures ANOVA. A significant main effect of condition indicated that jump height, RSI, impulse, and power-related variables were greater following the BFR than the sham condition across the post-conditioning assessment period. A significant main effect of time was also observed, with lower performance at 3 min compared to later time points. No condition-by-time interaction was found. These preliminary findings suggest that BWSSs performed under BFR conditions were associated with higher post-conditioning drop-jump performance than the sham condition. Low-load BFR exercise may therefore represent a practical strategy when heavy resistance equipment is unavailable. However, because no pre-conditioning baseline assessment was included, the magnitude of performance enhancement from baseline cannot be determined. Therefore, the findings should be interpreted as differences in post-conditioning performance between BFR and sham conditions rather than definite evidence of baseline to post enhancement.