High-pressure blood flow restriction acutely reduces maximal torque and power

Recent work has shown that blood flow restriction (BFR) during high-load resistance exercise may be able to acutely augment maximal strength and power, an effect that some hypothesize to be due to a rebound effect from a cuff inflated to a high pressure. However, less known is the role of high pressure independent of any such rebound effect. The objective of this study was to determine whether high-pressure BFR acutely influences strength and power during a concentric-only muscle action. Twenty-five resistance-trained individuals (14 males and 11 females) enrolled in a replicate cross-over trial, in which three paired cycles were completed (i.e., six experimental visits). Each paired cycle involved two visits that were completed in a random order and consisted of maximal strength and power testing (i.e., three maximal concentric knee extension repetitions for both) at either 150% of resting arterial occlusion pressure (150% AOP) or 2 mmHg (sham). Both peak torque (-17 (95% confidence interval (CI): -22.0, -12.7) Nm) and power (-33.9 (95% CI: -46.7, -21.2) W) decreased during the high-pressure BFR condition compared to the sham. Our results suggest that the previous acute strength and power benefits observed with high-load contractions likely are not explained by an independent pressure effect. No acute improvements in strength or power were observed in this investigation. The reason for the reduction in performance in the current study is not known, but we speculate that it may be related to the discomfort associated with contracting under high pressure.