Blood Flow Restriction Training for The Shoulder

Not Applicable

Completed

Conditions: Healthy

Interventions: Device: Blood flow restriction therapy

Registration Number: NCT04540367

Lead Sponsor: The Methodist Hospital Research Institute

Brief Summary: The aim of this study is to determine if BFR-LIX promotes greater increases in shoulder lean mass, rotator cuff strength, endurance, and acute increases in shoulder muscle activation compared to LIX alone.

Detailed Description: 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).

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 69

Inclusion Criteria

Healthy, untrained volunteers

Exclusion Criteria

Previous history of shoulder injury occurring in the laterality of choice
Current painful dysfunction resulting in exercise limitation
Any health-related exercise limitation as ordered by physician
Vascular compromise or previous vascular surgery
Ages outside of 18-65
Inability to access clinic and equipment
Currently involved in structured strength training regimen of the upper extremity

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Experimental: BFR	Blood flow restriction therapy	Participants in this group performed the exercises with the blood flow restriction therapy cuff

Primary Outcome Measures

Name	Time	Method
Determine if BFR Changes Shoulder Lean Muscle Mass in Pitchers	Baseline, 8 weeks	Shoulder lean muscle mass was measured in grams using DEXA. These data are reported for each arm.
Isometric Rotator Cuff Strength in General Population	Baseline and 8 weeks	Peak strength was measured using a hand-held dynamometer. A standardized procedure was used for shoulder strength testing, and all testing was performed by a sports-specialized (American Board of Physical Therapy Specialties Sports Clinical Specialist) physical therapist. A total of 6 different maximal isometric strength tests were used to measure the strength of the rotator cuff muscles in the following order: (1) seated forward flexion at 90 of shoulder abduction, (2) seated scaption at 90, (3) seated external rotation (ER) at 0, (4) seated internal rotation (IR) at 0, (5) prone ER at 90, and (6) prone IR at 90. Peak strength was measured using a microFET2 (Hoggan Scientific) hand-held dynamometer. For each isometric test, participants performed a 3-second maximal-exertion contraction against the dynamometer to determine peak strength. For each measure, tests were performed 3 times, and the highest value among the 3 trials was selected as the maximal strength value.
Isometric Rotator Cuff Strength in Pitchers	Baseline, 8 weeks	Peak strength was measured using a hand-held dynamometer. A standardized procedure was used for shoulder strength testing, and all testing was performed by a sports-specialized (American Board of Physical Therapy Specialties Sports Clinical Specialist) physical therapist. A total of 6 different maximal isometric strength tests were used to measure the strength of the rotator cuff muscles in the following order: (1) seated forward flexion at 90 of shoulder abduction, (2) seated scaption at 90, (3) seated external rotation (ER) at 0, (4) seated internal rotation (IR) at 0, (5) prone ER at 90, and (6) prone IR at 90. Peak strength was measured using a microFET2 (Hoggan Scientific) hand-held dynamometer. For each isometric test, participants performed a 3-second maximal-exertion contraction against the dynamometer to determine peak strength. For each measure, tests were performed 3 times, and the highest value among the 3 trials was selected as the maximal strength value.
Determine if BFR Changes UE Lean Muscle Mass in the General Population	Baseline and 8 weeks	UE lean muscle mass was measured in grams using DEXA. These data are reported as an average of both the left and right side.

Secondary Outcome Measures

Name	Time	Method
Strength Endurance in General Population	Baseline and 8 weeks	repetitions to fatigue (RTF) were performed for 3 exercises. Volume (repetitions x resistance, kg) was calculated for each trial as is common for strength training investigations. After strength testing, participants were asked to perform the first of 2 endurance tests separated by 48 to 72 hours. On both occasions, a single set of repetitions to fatigue (RTF) were performed for 3 exercises in the following order: standing cable ER at 0 of shoulder abduction, standing cable IR at 0, and dumbbell scaption with each exercise separated by a 2-minute rest period and alternating between arms (order randomized). This test was performed in both groups with and without 50% limb occlusion pressure (LOP) applied by an automated tourniquet system. A nylon cuff was placed around the most proximal portion of the upper extremity for all testing. The order of testing was randomized between the 2 testing days for each participant.