The Acute Effects of Continuous and Intermittent Blood Flow Restriction on Sprint Interval Performance and Muscle Oxygen Responses

The purpose of this investigation was to examine the effects of intermittent and continuous blood flow restriction (BFR) during sprint interval training (SIT) on muscle mitochondrial function and perceived effort. Fifteen men volunteered to participate in this investigation and were randomly assigned to complete SIT with CBFR, IBFR, and NoBFR. Each SIT session consisted of 2, 30s maximal sprints on a cycle ergometer with a resistance of 7.5% of body mass. Peak power (PP), total work (TW), ratings of perceived exertion (RPE), sprint decrement score (Sdec), and muscle oxygen responses were measured during each sprint. Before (pretest) and after (posttest) the sprints muscle mitochondrial functioning was assessed. There were similar reductions (17,835.6 ± 966.2 to 12,687.2 ± 675.2 J) in TW from Sprint 1 to Sprint 2 for all 3 conditions, and TW was lower (collapsed across Time) for CBFR (14,320.7 ± 769.1 J) than IBFR (15,548.0 ± 840.5 J) and NoBFR (15,915.4 ± 771.5 J). PP decreased to a greater extent from Sprint 1 to Sprint 2 during CBFR (25.5 ± 11.9%) and IBFR (23.4 ± 9.3%) than NoBFR (13.4 ± 8.6%). There were no differences in Sdec (84.3 ± 1.7 %, 86.1 ± 1.5 %, 87.2 ± 1.1%, for CBFR, IBFR and NoBFR, respectively) or RPE that increased from Sprint 1 (8.5 ± 0.3) to Sprint 2 (9.7 ± 0.1) among conditions. Muscle oxygen responses increased across time and were similar for IBFR and NoBFR, while changes in deoxyhemoglobin and total hemoglobin were greater for CBFR. Collectively, the findings of the present study indicated that applying BFR to maximal aerobic exercise is capable of eliciting acute physiological adaptations that may be superior with CBFR relative to IBFR and NoBFR