The Effects of Blood-flow Restriction Training on Bone Health at the Hip

Bloodflow restriction training (BFR) partially restricts arterial inflow and completely restricts venous outflow to the working muscle to promote chemical signals of fatigue and is hypothesized to realize musculoskeletal adaptation with lighter training loads and volume. PURPOSE: The purpose was to determine short-term training effects of BFR on bone health in college-aged students. METHODS: 19 males (20.2±1.5 years, 25.5±4.7 kg/m2) and 21 females (20.2±1.8years, 24.3±3.4 kg/m2) were placed into control group (CON) or BFR groups based on stratified randomization. Hip scans from dual-energy x-ray absorptiometry (DXA) were performed before and after 7 weeks of BFR training at 50% occlusion pressure and 20% of one-repetition maximum for four compound exercises over 4 sets with 30, 15, 15, and 15 reps. RESULTS: No significant between-group differences were observed. However, when pooled by sex group, narrow neck cross-sectional modulus of inertia (CSMI) trended favorably (0.03±2.8% BFR vs. - 3.18±2.6% CON, p=0.37) even though bone-mineral content (BMC) trended oppositely for males (3.33±2.8% BFR vs. -1.70±3.0% CON, p=.15) and females (-5.14±2.8% BFR vs. -1.64±2.6% CON, p=0.31 in females) while BMD trended downward in males (-1.12±1.2% BFR vs. 0.78±1.3% CON, p=0.20). CONCLUSION: This short-term BFR pilot-study intervention was ineffective at demonstrating beneficial skeletal adaptations. Trends for differential BMC and BMD by sex leading to favorable shifts in hip architecture for both sexes were not ruled out. These preliminary findings suggest a longer intervention with higher statistical power is warranted to determine the effect by which BFR training may improve markers of bone health.