Effects of Different Velocity Loss Thresholds in Full Squat With and Without Blood Flow Restriction on Strength...

This study aimed to analyze the effects of four full-squat (SQ) training programs that differed in the blood flow condition [free flow (FF) versus restricted (BFR)] and in the velocity loss (VL) induced within the set (20% vs. 40%) on strength gains and muscle hypertrophy. Fifty-two strength-trained men followed an 8-week (16 sessions) SQ training program from 55% to 70% 1-repetition maximum (1RM) (FF20: n = 14; BFR20: n = 13; FF40: n = 12; BFR40: n = 13). The number of sets n = 13 per session and the inter-set recovery periods (2 min) were matched between groups. A 50% arterial occlusion pressure was applied and maintained during the inter-set recovery for BFR groups. The following tests were carried out before and after the training intervention: (1) cross-sectional area of the vastus lateralis (ACSA); (2) countermovement jump; (3) progressive loading SQ test; and (4) fatigue SQ test. No significant BFR × VL × time interactions were observed. For 1RM and strength-derived outcomes from the progressive loading test, significant VL × time interactions (p = 0.01-0.05) in favor of 20% VL groups were found. Regarding jump performance, a significant VL × time interaction (p = 0.02) also favored the 20% VL groups. A BFR × time interaction (p = 0.02) was observed in favor of the BFR condition for ACSA. Prescribing a certain level of effort through VL results in similar jump and strength performance improvements, regardless of blood flow condition, with optimal gains achieved at a moderate VL threshold (20%). Additionally, the BFR condition maximized muscle hypertrophy compared to FF, making it a valuable strategy for muscle growth.