Effects of Blood Flow Restriction Combined with Aerobic Stepping Exercise in Sarcopenia: A Study Protocol for a Randomized Clinical Trial.

Background: Blood flow restriction training (BFRT) can produce effects similar to high-intensity exercise at lower intensities, making it a potentially more suitable method for older adults with sarcopenia. This study aims to determine the efficacy of the intervention on improving physical fitness in older adults with sarcopenia when blood flow restriction (BFR) and aerobic exercise (AE) are combined (BFR-AE) and to explore the related metabolic and signaling mechanisms.

Methods: This is a three-arm, parallel, randomized controlled trial. A total of 171 participants, aged 60 to 90 years, with sarcopenia will be randomly assigned (1:1:1) into one of three groups: a control group, an AE group, and a BFR-AE group. The participants in the control group will maintain their usual diet and activity habits. Those in the AE and BFR-AE groups will undergo a 12-week program of AE and BFR-AE respectively. The primary outcomes will include two long-term indicators: the 6-minutes walking test and 30-s chair stand test. Secondary outcomes will include additional long-term measures (eg, appendicular skeletal muscle mass index, handgrip strength, five-time chair stand test, lower extremity knee extensor and flexor muscle strength, sleep quality, emotion status, serum metabonomic and signal proteins), as well as instantaneous indicators (eg, blood pressure, heart rate, saturation of pulse oxygen, rating of perceived exertion, pain score and blood lactate concentration), adherence to exercise, and adverse events. Outcomes will be assessed at one of or all the time points of baseline, 12 and 24 weeks.

Discussion: It is expected that, after 12 weeks of intervention, both exercise groups will show improvements in cardiorespiratory and muscular fitness, with the BFR-AE group demonstrating greater benefits than the AE group alone.