Effects of exercise with and without different degrees of blood flow restriction on torque and muscle activation

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.