Strength and Jump Responses to Distinct Repetition Volumes Produced by Peak-Velocity-Decline and Failure-Based Set Termination during Low-Load Blood-Flow-Restriction Full Back Squat Training

Blood flow restriction (BFR) training is commonly prescribed with fixed repetition targets or sets to volitional failure, but these approaches may not individualize repetition exposure. This study compared strength and jump responses to the distinct working-set repetition volumes produced by two session-reference peak-velocity-decline thresholds and volitional failure during low-load BFR full back squat training. Forty-five resistance-trained males (22.9 ± 0.7 years) were allocated to a 10% peak-velocity-decline condition (VL10%), a 40% condition (VL40%), or volitional failure (FAIL; n = 15 each). All groups trained twice weekly for 8 weeks at 30% of the current one-repetition maximum (1RM) with BFR; the assigned set-termination strategy determined working-set repetition volume. Primary outcomes were full back squat 1RM and isometric mid-thigh pull net peak force; jump height and standing broad-jump distance were secondary outcomes. The strategies produced distinct working-set repetition volumes (55.91 ± 0.61, 74.26 ± 0.89, and 94.08 ± 0.93 repetitions per session in VL10%, VL40%, and FAIL, respectively; all adjusted p < 0.001). No statistically significant between-group difference was detected between VL40% and FAIL for the primary strength outcomes, while VL40% involved lower repetition volume and perceived exertion. VL10% reduced repetition volume further and showed favorable changes in countermovement-jump height and standing broad-jump distance, but smaller strength-oriented adaptations than VL40%. Under this low-load BFR protocol, no statistically significant differences were detected between VL40% and FAIL for the primary strength outcomes, whereas VL10% showed smaller improvements in both primary strength outcomes than VL40% and FAIL. Jump responses were outcome-specific: both VL10% and VL40% showed greater CMJ improvements than FAIL, VL40% showed greater SJ improvement than both VL10% and FAIL, and VL10% showed greater SBJ improvement than FAIL.