Effects Of Blood Flow Restriction With Eccentric Exercise On Muscle Adaptation

Abstract

PURPOSE: BFR during RT has been reported clinically to rehabilitate/prevent injury in healthy people and people with orthopedic conditions. Further, subjective accounts of minimal muscle soreness post-training suggest a reduction in exercise induced muscle damage compared to traditional RT. We sought to compare the effects of BFR eccentric RT at low loads on muscle performance to traditional eccentric resistance training at high loads, and to explore the feasibility of multifrequency bioelectric impedance analysis (BIA) to assess muscle damage and hypertrophy. METHODS: 25 healthy young adults 25 ± 5yo (11female,14alen) were randomized into two groups (BFR L, BFR R and trained 2x/wk for 6 wks. The contralateral leg was trained traditionally to serve as the control (TC) after baseline testing (single-leg vertical jump, Nordbord bilateral eccentric hamstring strength, legcurl bilateral 1RM, legcurl hamstring endurance)At the conclusion, participants re-tested. BIA data was collected pre (0, 24, 48hrs) and post (0, 24, 48hrs). Pre-post paired t-tests and coefficient of determination were used for analysis. RESULTS: There was 96% compliance. There were no significant changes in single leg vertical jump (left:p= 0.14, right:p= 0.26), hamstring strength (left:p= 0.17, right: p= 0.38), or hamstring endurance in either leg (left:p= 0.95, right: p= 0.12) or condition. There were significant increases (7.5-9.5%) in hamstring 1RM in both legs (left:p < 0.01, right:p < 0.01) and both training conditions (BFR:p < 0.01, TC:p < 0.01) .There was low correlation between phase angle and participant perceived soreness (r2=0.15), but scores were significantly lower in BFR leg immediately (p=0.04) and 24hr (p=0.04) post training. CONCLUSIONS: Eccentric BFR resistance training exhibited similar outcomes to traditional training with less reported soreness. However, interpretation of these data are limited by methodologic approach.