Comparison of low-load resistance exercise with (BFR) and without blood flow restriction (NBFR) to volitional exhaustion on muscle swelling. Eight young men (aged 27[SD 5]years, standing height 1.74[SD 0.05]m, body mass 70.3[SD 4.3]kg) performed 20% of one repetition maximal dumbbell curl exercise to exhaustion (4 sets, rest intervals were 30-sec for BFR and or 3-min for NBFR, respectively). One arm was randomly chosen for BFR exercise and the other arm performed NBFR exercise. During the BFR exercise session, subjects placed elastic cuff proximally on testing arm at 160 mmHg. Electromyography (EMG) signals were recorded from surface electrodes placed on the biceps brachii muscle and analyzed for integrated EMG (iEMG). Biceps brachii muscle thickness (MTH) were measured using B-mode ultrasound. During exercise session, iEMG for biceps brachii muscles increased (p<0.01) progressively during BFR and NBFR (3.52 and 3.70 times of baseline value). Immediately after the exercise, MTH acutely increased (p<0.01) with BFR and NBFR (1.23 and 1.19 times of baseline value). These results demonstrate that BFR and NBFR exercises lead to pronounced muscle activation and muscle swelling, which were similar between two conditions. Thus, it can be speculated that the magnitude of increase in muscle size following low-load resistance training is similar between BFR and NBFR.

DESCENTE SPORTS SCIENCE Vol.35/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE