If you're a young guy new to weightlifting and you use a blood pressure cuff to restrict blood flow while lifting, it doesn't matter whether you squeeze the cuff while you're pushing the weight up or while you're resting between sets—either way, you'll gain the same amount of strength and muscle.

Young, untrained men perform two separate high-load resistance training sessions over two distinct 8-week periods: one with blood flow restriction applied during contractions, and another with restriction applied during rest intervals. The order is randomized and counterbalanced, with a 4-week washout between conditions. Muscle strength (1RM) and hypertrophy (ultrasound or DEXA-measured muscle cross-sectional area) are measured at baseline, mid-point, and end of each phase.

Two matched groups of young, untrained men are assigned to either BFR during contractions or BFR during rest intervals, both performing identical high-load resistance training for 12 weeks. Outcomes (strength and hypertrophy) are measured at baseline and post-intervention using standardized protocols. Groups are matched for age, baseline strength, and training history.

Each participant completes three 4-week training blocks: one with no BFR, one with BFR during contractions, and one with BFR during rest intervals, in randomized order with 2-week washouts. All training volume, load, and rest periods are strictly controlled. Strength and muscle size are measured at the end of each block.

A cohort of young, untrained men is recruited and assigned to one of two training protocols based on trainer preference: BFR during contractions or BFR during rest intervals. All participants follow identical training schedules for 10 weeks. Strength and hypertrophy are measured at baseline and end, with covariates (sleep, diet, compliance) tracked.

A group of 10 young, untrained men undergo 8 weeks of high-load resistance training with BFR applied during contractions, followed by 8 weeks with BFR applied during rest intervals, in a fixed sequence. Strength and hypertrophy are measured at baseline, after each 8-week phase, and at end.