Electromyographic Response to Blood Flow Restriction Exercise in Healthy Adults

This pilot randomized contralateral within-participant study evaluated the immediate neuromuscular response to low-load knee extension exercise performed with and without blood flow restriction in healthy young adults. Participants were randomized in a 1:1 ratio to one of two limb-allocation groups: blood flow restriction applied to the dominant limb or blood flow restriction applied to the non-dominant limb. In each participant, the contralateral limb completed the same exercise protocol without blood flow restriction. Therefore, all participants were assessed under both experimental conditions. Both limb-specific conditions were completed during the same experimental session. The order of the blood flow restriction and non-blood flow restriction conditions was randomized for each participant, with a 10-minute rest period between conditions. Blood flow restriction was applied using a pneumatic cuff positioned on the proximal thigh. Cuff pressure was individualized and set at 80% of the arterial occlusion pressure measured for the corresponding limb. Participants completed the same standardized low-load knee extension protocol under both conditions. Surface electromyography was used to record vastus lateralis activity from each assessed limb during the exercise protocol. Muscle activity was primarily evaluated using root mean square amplitude normalized to the pre-exercise maximal voluntary isometric contraction recorded from the corresponding limb. Root mean square amplitude during maximal voluntary isometric contraction trials was also recorded before and immediately after each condition. The study aimed to compare the electromyographic response between the blood flow restriction and non-blood flow restriction conditions and to determine whether this response differed according to whether blood flow restriction was applied to the dominant or non-dominant limb.

Inclusion Criteria: * Age between 18 and 65 years. * Healthy adults. * Absence of active pain or musculoskeletal injury in the lower limbs at the time of assessment. * Ability to understand the study procedures. * Voluntary agreement to participate and provision of written informed consent. Exclusion Criteria: * History of neuromuscular disease. * History of cardiovascular disease. * History of peripheral vascular disease. * History of thromboembolic events. * Uncontrolled hypertension. * Skin lesions or skin conditions preventing placement of the blood flow restriction cuff or surface electromyography electrodes. * Recent lower limb surgery. * Pregnancy. * Any other contraindication to blood flow restriction exercise.