Blood Flow Restriction Training for The Shoulder

Healthy Volunteers: Thirty-two healthy adults were randomized into two groups (BFRm=13,f=3, NoBFRm=10,f=6) that performed 8wks of shoulder LIX \[2/wk, 4 sets (30/15/15/fatigue), 20%max\] using common rotator cuff exercises \[cable external rotation (ER), cable internal rotation (IR), dumbbell scaption (SCAP), and side-lying dumbbell ER (SLER)\]. The BFR group also trained with an automated tourniquet placed at the proximal arm (50%-occlusion). Regional lean mass (dual-energy-xray-absorptiometry), isometric strength, and muscular endurance (repetitions-to-fatigue, RTF, 20%max, with and without 50%-occlusion) was measured before and after training. Electromyographic amplitude (EMGa) was also recorded from target shoulder muscles during endurance testing. A mixed-model ANCOVA (covaried on baseline measures) was used to detect within and between-group differences in primary outcome measures (α=0.05). Pitchers: Twenty-eight collegiate baseball pitchers were randomized into 2 groups (BFRN=15, NOBFRN=13) that, in conjunction with offseason training, performed 8wks of shoulder LIX \[Throwing arm only; 2/wk, 4 sets (30/15/15/fatigue), 20%isometric max\] using 4 exercises \[cable external and internal rotation (ER/IR), dumbbell scaption, and side-lying dumbbell ER\]. The BFR group also trained with an automated tourniquet on the proximal arm (50%-occlusion). Regional lean mass (dual-energy x-ray absorptiometry), rotator cuff strength (dynamometry: IR0\&90, ° ER0\&90, ° Scaption, Flexion), and fastball biomechanics were assessed pre- and post-training. Achievable workload (sets × reps × resistance) was also recorded. An ANCOVA (covaried on baseline measures) repeated on training timepoint was used to detect within-group and between-group differences in outcome measures (α=0.05). For significant pairwise comparisons, effect size (ES) was calculated using a Cohen's d statistic and interpreted as: 0-0.1, negligible(N); 0.1-0.3, small(S); 0.3-0.5, moderate(M); 0.5-0.7, large(L); \>0.7, very large(VL).