The Proximal and Distal Effects of Blood Flow Restriction Therapy on Upper and Lower Extremity Strengthening: A Randomized Controlled Trial

Abstract

Objectives: Blood flow restriction (BFR) therapy consists of low-intensity exercise performed under reduced venous return due to an inflatable tourniquet. This produces similar physiologic and clinical effects to high-intensity routines with less joint and tissue stress. Postoperative patients may benefit from more efficient rehabilitation. Proximal and distal effects of BFR have been evaluated, however, minimal literature exists on its use in orthopaedic conditions. The purpose of this study was to determine the effects of low-intensity BFR therapy both proximal and distal, in the upper and lower extremities. Methods: This was a prospective, randomized controlled trial of healthy subjects completing a standardized 6-week course of BFR therapy. Subjects were randomized to BFR therapy on one extremity or to a control group. Subjects were excluded for cardiac, pulmonary, or hematologic disease, pregnancy, or previous surgery in the extremity. Data collected at baseline and completion included: limb circumferences, isokinetic, and manual strength testing. Results: Forty subjects completed the protocol. Average age was 27.7 years; 54% were female. For both upper and lower extremity groups, a statistically significant increase was observed in manual and isokinetic strength both proximal and distal to the BFR tourniquet when compared to both the non-tourniquet extremity and the control group (p<0.05). Limb circumference significantly increased in the upper (p<0.01) and lower extremities (p=0.02). A significant increase in manual strength was noted in shoulder abduction and scaption, and hip extension and abduction even in the non-tourniquet BFR extremity compared to the control group (p<0.05). Conclusion: Low-intensity BFR therapy led to greater increases in muscle strength and hypertrophy. Similar strengthening effects were seen in proximal and distal muscle groups. Strength increases in the contralateral BFR extremity may corroborate a systemic effect. This study provides data to further evaluate the efficacy and safety of BFR therapy in operative and non-operative orthopaedic conditions. [Table: see text]

Blood Flow Restriction Training for the Shoulder: A Case for Proximal Benefit

“…This investigation was approved by our institutional review board for performing research involving human participants, and all volunteers provided informed consent before participating. Before the investigation began, data were pooled from previous strength training investigations 4,24,35,37,44 as well as from pilot BFR investigations performed in our laboratory and clinic. 34 Based on a power of 0.80 at a = .05 with a minimum within-group detectable difference (pre-to posttraining) of 5% in upper extremity lean mass and 10% in isometric rotator cuff strength (primary outcome variables), it was determined that a minimum of 15 participants would be required per group.…”

Blood Flow Restriction Therapy Preserves Lower Extremity Bone and Muscle Mass After ACL Reconstruction

“…The institutional review board for research involving human subjects approved all protocols presented here. Before beginning the investigation, data from previous training investigations, 7,26,30 as well as from pilot BFR investigations, 27 were analyzed. Based on a power of 0.80 at α = 0.05 with a minimum between-group detectable effect size (ES) of 0.5 and within-group detectable difference (pre- to postrehabilitation) of 5% in leg LM and BMD at the distal femur and proximal tibia, it was determined that a minimum of 15 participants per group would be required.…”

Application of Current Knowledge of Blood Flow Restriction Training for Use on Upper Extremity Injuries

“…Due to certain restrictions, the combined lowload resistance training and vascular occlusion that occurs with BFR can be used for the types of patients previously mentioned, or others who are physically unable to perform resistance exercises with an 80% maximum load. Although these populations may have different goals for their clinical outcomes, the versatility of BFR makes it an optimal training intervention (American College of Sports Medicine position stand 2009; Bowman, El-shaar, Milligan, et al 2019;Libardi et al 2015;Lu et al 2020;Scott et al 2016;Wilk et al 2020). Previous research has examined the use of BFR with lower extremity injuries (e.g., ACL tears); however, few studies have examined the combination of low-load resistance training with BFR in upper extremity exercises (Barber-Westin and Noyes 2019; Dankel et al 2016;Hughes et al 2017).…”