Passive Blood Flow Restriction Accelerates Muscle Recovery After Exercise-Induced Muscle Damage in Healthy, Recreationally Active Females.

The purpose of this investigation was to examine the effects of passive blood flow restriction (pBFR) on indices of exercise-induced muscle damage (EIMD) following a muscle-damaging protocol. Eighteen females completed 6 visits occurring at the same time of day (±2 hours). Muscle damage was elicited by performing 3 sets of 25 maximal, unilateral, isokinetic (60·s -1 ), concentric-eccentric leg extensions on each leg. Each leg was then randomly assigned to receive pBFR (80% of total arterial occlusion pressure) or sham (20 mmHg) at 0, 24, 48, 72, and 96 hours post-EIMD. Indices of EIMD (muscle soreness [0-10 visual analog scale], limb circumference, range of motion [ROM], pain pressure threshold, and maximal voluntary isometric contraction [MVIC] torque) were assessed before EIMD (baseline) and at 0, 24, 48, 72, and 96 hours. Separate 2 (Condition [pBFR and sham]) × 6 (Time [baseline, 0, 24, 48, 72, and 96 hours]), repeated-measures ANOVAs were performed. Collapsed across Condition, muscle soreness increased post-EIMD and partially recovered at 72 and 96 hours (change from baseline [Δ]; Δ2.3 ± 2.3 au and Δ1.4 ± 1.5 au, respectively). Limb circumference increased in both conditions post-EIMD and recovered by 24 hours (pBFR: Δ0.4 ± 1.8 cm; sham: Δ0.5 ± 2.2 cm). ROM recovered sooner for pBFR (24 hours; Δ-6.1 ± 8.9°) than sham (24 hours; Δ-9.2 ± 9.4°), and ROM was greater for pBFR than sham at 48 hours post-EIMD. Pain pressure threshold was greater, collapsed across Time, for pBFR (4.40 ± 1.62 kgf) than sham (4.12 ± 1.63 kgf). Like ROM, MVIC torque recovered sooner for pBFR (24 hours; Δ-14.9 ± 25.3 Nm) than sham (24 hours; Δ-33.9 ± 22.1 Nm). Applying pBFR after EIMD resulted in a faster rate of return for MVIC and ROM in females, suggesting that pBFR may serve as an effective strategy to facilitate recovery of muscle function.