Effects of low-intensity concentric and eccentric exercise combined with blood flow restriction on indices of exercise-induced muscle damage

Low-intensity blood-flow restriction (BFR) resistance training significantly increases strength and muscle size, but some studies report it produces exercise-induced muscle damage (EIMD) in the lower body after exercise to failure. Purpose To investigate the effects of a pre-set number of repetitions of upper body concentric and eccentric exercise when combined with BFR on changes in EIMD. Methods Ten young men had arms randomly assigned to either concentric BFR (CON-BFR) or eccentric BFR (ECC-BFR) dumbbell curl exercise (30% one-repetition maximum (1-RM), 1 set of 30 repetitions followed by 3 sets of 15 repetitions). Maximal isometric voluntary contraction force (MVC), muscle thickness (MTH), circumference, range of motion (ROM), ratings of perceived exertion (RPE), and muscle soreness were measured before, immediately after, and daily for 4 days post-exercise. Results MVC decreased by 36% for CON-BFR and 12% for ECCBFR immediately after exercise but was not changed 1–4 days post-exercise ( p > 0.05). Only CON-BFR had significant changes in MTH and circumference immediately after exercise ( p < 0.05). Muscle soreness was observed in the ECC-BFR arm at 1 and 2 days after exercise. Conclusions Low-intensity ECC-BFR produces significant muscle soreness at 24 h but neither ECC-BFR nor CON-BFR exercise produces significant changes in multiple indices of EIMD.