Acute Effects of Sprint Interval Training and Blood Flow Restriction on Neuromuscular and Muscle Function

Objectives: This investigation examined the effects of continuous (CBFR) and intermittent (IBFR) blood flow restriction (BFR) applied during sprint interval training (SIT) on performance and neuromuscular function. Methods: Fifteen men completed a randomized bout of SIT with CBFR, IBFR, and without BFR (No-BFR), consisting of 2, 30-s maximal sprints on a cycle ergometer with a resistance of 7.5% of body mass. Concentric peak torque (CPT), maximal voluntary isometric contraction (MVIC) torque, and muscle thickness (MT) were measured before and after SIT, including surface electromyography (sEMG) recorded during the strength assessments. Peak and mean revolutions per minute (RPM) were measured during SIT and power output was examined relative to physical working capacity at the fatigue threshold (PWCFT). Results: CPT and MVIC torque decreased from pre-SIT (220.3 +/- 47.6 Nm and 355.1 +/- 72.5 Nm, respectively) to post-SIT (147.9 +/- 27.7 Nm and 252.2 +/- 45.5 Nm, respectively, all P<0.05), while MT increased (1.77 +/- 0.31 cm to 1.96 +/- 0.30 cm). sEMG mean power frequency decreased during CPT (-12.8 +/- 10.5%) and MVIC (-8.7 +/- 10.2%) muscle actions. %PWCFT was greater during No-BFR (414.2 +/- 121.9%) than CBFR (375.9 +/- 121.9%). Conclusion: SIT with or without BFR induced comparable alterations in neuromuscular fatigue and sprint performance across all conditions, without affecting neuromuscular function.