Acute effects of high-intensity interval exercise combined with different blood flow restrictions on hemodynamic and muscle oxygenation responses in junior rowers

Abstract

Introduction: High-intensity interval training (HIIT) is known to improve endurance performance, yet the physiological effects of combining high-intensity interval exercise (HIIE) with blood flow restriction (BFR) are not fully understood. This study aimed to identify the optimal HIIE+BFR protocol for enhancing hemodynamic and muscle oxygenation responses in young rowers. Methods: Fourteen junior rowers (11 males, 3 females) completed four HIIE sessions on a rowing ergometer with different arterial occlusion pressures (AOPs): HIIE alone, HIIE+40%AOP, HIIE+50%AOP, and HIIE+60%AOP, following a randomized crossover design. Each session included four 2-min rowing bouts at 90% VO2max, separated by 2 min of passive recovery, with trials spaced 7 days apart. Cardiac output (CO), stroke volume (SV), heart rate (HR), muscle oxygen saturation (SmO2), rating of perceived exertion (RPE), and pain were continuously monitored throughout each session. Results and Discussion: Overall, mean SmO2max increased with higher AOPs (%AOP) across sets. Mean SmO2min differed significantly between conditions, with the lowest value observed at 50% AOP compared to other BFR conditions. The mean ∆SmO2diff in the HIIE-alone condition did not change across sets, whereas in all BFR conditions, ∆SmO2diff progressively increased across sets (all, p < 0.05). Mean SV, CO, and HR gradually increased from set 1 to set 2 and slightly declined from set 3 to set 4, regardless of BFR condition. RPE values increased from set 1 to set 4 across all conditions (all, p < 0.05). In contrast, pain scores were significantly higher in all BFR conditions compared to HIIE alone (p = 0.00), with the highest values observed in HIIE+60%AOP, exceeding those in HIIE+50%AOP and HIIE+40%BFR (all, p < 0.05). Conclusion: Combining HIIE with BFR at 50% AOP appears effective in promoting muscle deoxygenation while remaining more tolerable for junior rowers. Thus, this BFR training approach can be used to enhance peripheral adaptations and improve physical performance in rowers.