CONTEXT: Blood flow restriction (BFR) training utilizes a tourniquet, applied to the proximal portion of one or more extremities, to occlude blood flow during exercise. Significant gains in strength and cross-sectional area can be achieved in muscles, both distal and proximal to BFR cuff application. PURPOSE: To compare strength gains of the rotator cuff and changes in tendon size in subjects who performed side-lying external-rotation exercise with or without BFR. METHODS: Forty-six subjects (mean age 25.0 [2.2] y) were randomized to either a BFR + exercise group or to the exercise-only group. Subjects performed 4 sets of the exercise (30/15/15/15 repetitions) at 30% 1-repetition maximum 2 days per week for 8 weeks. RESULTS: Subjects in both groups experienced strength gains in the supraspinatus and the external rotators (P = .000, P = .000). However, there was no difference in strength gains between groups for the supraspinatus (P = .750) or the external rotators (P = .708). Subjects in both groups experienced increases in supraspinatus tendon thickness (BFR P = .041, exercise only P = .011). However, there was no difference between groups (P = .610). CONCLUSIONS: Exercise with BFR applied to the proximal upper extremity did not augment rotator cuff strength gains or tendon thickness when compared with subjects who only exercised. This study did demonstrate that performing multiple sets of high repetitions at a low load led to significant increases in rotator cuff strength and tendon size in the dominant upper extremity.
CONTEXT: Blood flow restriction (BFR) training utilizes a tourniquet, applied to the proximal portion of one or more extremities, to occlude blood flow during exercise. Significant gains in strength and cross-sectional area can be achieved in muscles, both distal and proximal to BFR cuff application. PURPOSE: To compare strength gains of the rotator cuff and changes in tendon size in subjects who performed side-lying external-rotation exercise with or without BFR. METHODS: Forty-six subjects (mean age 25.0 [2.2] y) were randomized to either a BFR + exercise group or to the exercise-only group. Subjects performed 4 sets of the exercise (30/15/15/15 repetitions) at 30% 1-repetition maximum 2 days per week for 8 weeks. RESULTS: Subjects in both groups experienced strength gains in the supraspinatus and the external rotators (P = .000, P = .000). However, there was no difference in strength gains between groups for the supraspinatus (P = .750) or the external rotators (P = .708). Subjects in both groups experienced increases in supraspinatus tendon thickness (BFR P = .041, exercise only P = .011). However, there was no difference between groups (P = .610). CONCLUSIONS: Exercise with BFR applied to the proximal upper extremity did not augment rotator cuff strength gains or tendon thickness when compared with subjects who only exercised. This study did demonstrate that performing multiple sets of high repetitions at a low load led to significant increases in rotator cuff strength and tendon size in the dominant upper extremity.