75‐repetition versus sets to failure of blood flow restriction exercise on indices of muscle damage in women

Abstract

ABSTRACTThere is conflicting evidence regarding the prevalence and magnitude of exercise‐induced muscle damage (EIMD) following low‐load resistance exercise with blood flow restriction (LL + BFR) that may be related to exercise protocols. The purpose of this investigation was to examine the effects of 75‐repetition (BFR‐75) (1 × 30, 3 × 15) and 4 sets to failure (BFR‐4x) protocols on indices of EIMD among untrained women. Thirteen women completed this investigation. One leg was randomly assigned to BFR‐75 and the other to BFR‐4x. Each leg performed isokinetic, unilateral, concentric‐eccentric, leg extension muscle actions at 30% of maximal strength. Indices of EIMD (muscle soreness, range of motion [ROM], limb circumference, pain pressure threshold [PPT], and maximal voluntary isometric contraction [MVIC]) were recorded before exercise, 0‐, 24‐, 48‐, 72‐, and 96‐hours post‐exercise. There were no changes for ROM, circumference, or PPT. Muscle soreness increased similarly in both conditions 0‐, 24‐, and 48‐hours post‐exercise and MVIC increased 24‐, 48‐, 72‐, and 96‐hours post‐exercise. These findings suggested BFR‐75 and BFR‐4x were not associated with EIMD and elicited similar physiological responses. The increases in muscle soreness may be due to metabolic stress associated with LL + BFR protocols apart from EIMD.