Blood Flow Restriction during Rest Periods of High-Intensity Interval Training Enhances Endurance Performance: A Randomized Placebo-Controlled Study

ABSTRACT Purpose This study investigated the effects of incorporating blood flow restriction (BFR) during rest periods between sets of high-intensity interval training (HIIT) on aerobic, sprint, and muscular performance in recreationally active participants. Methods Forty healthy males (28.7 ± 6.0 yr) were pair matched and randomized into either blood flow restriction (BFR + HIIT) or sham (SHAM + HIIT) groups and completed nine sessions of HIIT (three sets, 8 × 30 s cycling at 90%–105% maximal aerobic power (W max ), 30 s active recovery, with 4 min rest between sets) over 3 wk. The BFR + HIIT group had 80% limb occlusion pressure applied for the first 2 min of rest between sets, whereas the SHAM + HIIT group cycled under sham hypoxic conditions. Results Training variables (power output, heart rate, perceived effort, and pain) were similar between groups. Posttraining, endurance performance significantly improved in BFR + HIIT compared with SHAM + HIIT, indicated by greater increases in W max (+25.6 vs +17.2 W, P = 0.014) and time to exhaustion (+61.7 vs +38.4 s, P = 0.008) during an incremental graded cycling test, and increased mean power output (TT MPO : +20.3 vs +9.3 W, P = 0.017) and reduced time to completion (−79.1 vs −39.3 s, P = 0.014) during a 20 km time trial. Conversely, no differences were found between groups in power outputs assessed by the 30 s cycling sprint test, or in muscular power and strength, as measured by countermovement jump and isometric mid-thigh pull tests. Conclusions Using BFR during rest periods of HIIT enhances aerobic performance without altering training variables, although it may not provide additional advantages for sprint power or strength development.