Proximal, Distal, and Contralateral Effects of Blood Flow Restriction Training on the Lower Extremities: A Randomized Controlled Trial. (March 2019)

• Record Type: Journal Article
• Authors: Bowman, Eric N.; Elshaar, Rami; Milligan, Heather; Jue, Gregory; Mohr, Karen; Brown, Patty; Watanabe, Drew M.; Limpisvasti, Orr
• Is Part Of: Sports health. Volume 11:Number 2(2019:Mar./Apr.)
• Page Start: 149
• Page End: 156
• Publication Date: 2019-03
• Subjects: blood flow restriction -- BFR -- therapy -- lower extremity; Sports medicine -- Periodicals; Athletic Injuries -- Periodicals; Physical Education and Training -- Periodicals; Musculoskeletal Physiological Phenomena -- Periodicals; Médecine du sport -- Périodiques; 617.1027
• DOI: 10.1177/1941738118821929
• Languages: English
• ISSNs: 1941-7381

Abstract

Background: Blood flow restriction (BFR) training involves low-weight exercises performed under vascular occlusion via an inflatable cuff. For patients who cannot tolerate high-load exercises, BFR training reportedly provides the benefits of high-load regimens, with the advantage of less tissue and joint stress. Hypothesis: Low-load BFR training is safe and efficacious for strengthening muscle groups proximal, distal, and contralateral to tourniquet placement in the lower extremities. Study Design: Randomized controlled trial. Level of Evidence: Level 1. Methods: This was a randomized controlled trial of healthy participants completing a standardized 6-week course of BFR training. Patients were randomized to BFR training on 1 extremity or to a control group. Patients were excluded for cardiac, pulmonary, or hematologic disease; pregnancy; or previous surgery in the extremity. Data collected at baseline and completion included limb circumferences and strength testing. Results: The protocol was completed by 26 patients, providing 16 BFR and 10 control patients (mean patient age, 27 years; 62% female). A statistically greater increase in strength was seen proximal and distal to the BFR tourniquet when compared with both the nontourniquet extremity and the control group ( P < 0.05). Approximately twice the improvement was seen in the BFR group compared with controls. Isokinetic testing showed greater increases in knee extension peak torque (3% vs 11%), total work (6% vs 15%), and average power (4% vs 12%) for the BFR group ( P < 0.04). Limb circumference significantly increased in both the thigh (0.8% vs 3.5%) and the leg (0.4% vs 2.8%) compared with the control group ( P < 0.01). Additionally, a significant increase occurred in thigh girth (0.8% vs 2.3%) and knee extension strength (3% vs 8%) in the nontourniquet BFR extremity compared with the control group ( P < 0.05). There were no reported adverse events. Conclusion: Low-load BFR training led to a greater increase in muscle strength and limb circumference. BFR training had similar strengthening effects on both proximal and distal muscle groups. Gains in the contralateral extremity may corroborate a systemic or crossover effect. Clinical Relevance: BFR training strengthens muscle groups proximal, distal, and contralateral to cuff placement. Patients undergoing therapy for various orthopaedic conditions may benefit from low-load BFR training with the advantage of less tissue stress.