Impact of early and late morning supervised blood flow restriction training on body composition and skeletal muscle performance in older inactive adults

Objectives To investigate the impact of a supervised blood-flow restriction (BFR) training program performed at different times of the morning on body composition and muscle performance in older, inactive adults. Methods A single-arm intervention of supervised BFR resistance training was performed three times per week for six weeks. Participants (n=24; aged 65+ years) were categorized into early morning (n=13; 05:00–08:59) or late morning (n=11; 09:00–12:00) groups. Primary outcomes were changes in body composition, total work, average peak power, average peak torque, muscle strength, and physical function. Results Mixed model analysis of variance revealed a significant within-subject effect of time for all strength measures (p ranging from 0.017 to <0.001) and some physical function measures including the 30 s chair stand test, 30 s bicep curl test, and grip strength (p ranging from 0.015 to <0.001). No between-group or time by group interaction effect was observed for all outcomes. Conclusions This study showed that only six weeks of BFR training, performed at different time of the morning, did not enhance muscle mass and performance, but provided similar changes in muscle strength and some physical function tests in older adults.