Does exercise with different degrees of blood flow restriction alter torque and muscle activation?
Different levels of blood flow restriction alter acute muscular response, but higher pressures do not augment these changes beyond 50% arterial occlusion.
INTRODUCTION: An unresolved question in resistance training combined with blood flow restriction (BFR) is what percentage of estimated arterial occlusion pressure provides the most robust acute muscular response. METHODS: Forty participants were assigned to Experiments 1, 2, or 3. Each experiment completed exercise protocols differing by pressure, exercise load, and/or volume. Torque was measured pre- and postexercise, and muscle activation was measured pre- and during each set. RESULTS: Pressure and load did not affect torque greatly. Muscle activation increased in all conditions (P < 0.05) and was higher with 30% 1RM compared with 20% 1RM. Pressure appeared to increase muscle activation from 40% to 50% arterial occlusion 66% vs. 87% maximal voluntary contraction (30% 1RM) but was not further increased with higher pressure. CONCLUSION: Different levels of BFR may alter the acute muscular response to a degree, although higher pressures do not appear to augment these changes.
Loenneke et al. (2014) studied this question.