B.F.R. For Proximal Benefit: Blood Flow Restriction Therapy For The Shoulder?

Abstract

Blood flow restriction (BFR) therapy has been observed to improve post-operative recovery in the limbs when combined with low intensity resistance exercise (LIX). Little data exists regarding use of BFR for proximal benefit of the upper limbs (shoulders). PURPOSE: (1) Determine if rotator cuff (RC) exercises combined with BFR (BFR-Rx) promote greater increases in strength, muscular endurance, and lean mass compared to exercise alone (NoBFR-Rx); (2) Determine if BFR applied to the arm during acute LIX increases activation of RC muscles. METHODS: Eighteen healthy adults (♂11, 32±5yr, 92.3±15.2kg | ♀7, 34±7yr, 81.9±6.3kg) were recruited and randomized into 2 groups (BFR-Rx, NoBFR-Rx). Each performed 8wks of LIX (2/wk) using 4 RC exercises: cable external rotation (ER), cable internal rotation (IR), dumbbell scaption, and side-lying dumbbell ER; 20%1RM; 1set/30reps followed by 3sets/15reps (30s rest between sets, 2min rest between exercises, ^1lb resistance each week all repetitions achieved). For the BFR-Rx group, BFR was applied to using an tourniquet system (Delfi®) that maintained 50% limb occlusion pressure during each exercise with pressure released between exercises. A group x time ANCOVA (co-varied on baseline) followed by a tukey’s post hoc test was used to detect absolute & relative changes in strength (pre/post training), lean mass (pre/post training; DEXA, GE®), and achieved weekly exercise volume (sets x reps x resistance). A two-tailed paired samples t-test was used to detect differences in RC muscle activation (EMG, Delsys®) recorded during acute ER and IR fatigue tests in all subjects. Type I error was set at α=0.05. CONCLUSIONS: Combined BFR-Rx using RC exercises may yield greater increases in shoulder/arm lean mass, strength, and muscular endurance compared to exercise alone. These findings may be partially due to a greater activation of shoulder musculature while using BFR. Data collection is ongoing and will be completed prior to conference.