Blood flow restriction increases metabolic stress but decreases muscle activation during high‐load resistance exercise

Abstract

ABSTRACTIntroduction: We investigated differences in metabolic stress (lactate) and muscle activation (electromyography; EMG) when high‐load resistance exercise (HL) is compared with a condition in which blood flow restriction (BFR) is applied during the exercise or during the rest interval. Methods: Twelve participants performed HL with BFR during the intervals (BFR‐I), during the set (BFR‐S), and without BFR. Each condition consisted of 3 sets of 8 repetitions with knee extension at 70% of 1‐repetition maximum. Lactate and root mean square (RMS) from the surface EMG of the vastus lateralis were calculated. Results: Lactate increased in all protocols but was higher with BFR‐I than with BFR‐S and HL. RMS decreased under all conditions, with a larger effect size in BFR‐I (1.47) than in BFR‐S (0.66) and HL (0.59). Discussion: BFR‐I increases lactate, possibly as a result of reduced restoration of ATP. Muscle activation seems to be impacted by mechanical stress but may be reduced by metabolic stress. Muscle Nerve 57: 107–111, 2018