Blood Flow Restriction Training for The Shoulder: A Case for Proximal Benefit
Phase: NA
Conditions: Healthy
Sponsor: The Methodist Hospital Research Institute

Cover Page 
The effect of blood flow restriction training on rotator cuff strength in the healthy, untrained shoulder 
Date: July 19, 2019 
Pro00017362 
NCT: 04530367 
Status: Closed 12/7/2021 

1) Protocol Title 
The effect of blood flow restriction training on rotator cuff strength in the healthy, untrained 
shoulder 
 
2) Investigator  
Patrick McCulloch, MD 
 
3) Objectives  
The aim of this study will be to determine the effect of upper extremity (UE) blood flow 
restriction (BFR) training for muscular strength improvement in individuals with no history of 
previous shoulder injury.  The authors hypothesize that, participants who partake in BFR training 
will experience greater strength gains compared to a control group performing the same 
exercises. 
 
4) Background  
BFR training has been gaining popularity as a novel technique to develop greater strength and 
muscle mass in the rehabilitation setting.  Many high-quality studies have examined the effects 
of muscle growth following controlled programs targeting strengthening at lower loads than 
typically used for hypertrophy.  In rehabilitation, this provides the patient a significant advantage 
when muscular weakness and poor neuromuscular control predominate following an injury or 
surgery.  If an individual is able to attain measurable improvements in muscle function utilizing 
low loads, then rehabilitation can be safer and more productive. 
 
Recent publications have described the effects of BFR with exercise, including increases in 
muscle fiber hypertrophy at the cellular level12,17,19,20, muscle size and strength improvements 
with various methods of exercise2,6,10,26, and decreased muscle atrophy following injury or 
surgery.14,21  In resistance training, muscle hypertrophy is carried out by mechanical tension and 
metabolic stress.  It’s hypothesized that metabolic stress factors play the dominant role in BFR 
training.1  In horses, somatotropin, a hormone that induces the release of growth hormone, is 
significantly increased after a BFR walk for 5 minutes as compared with a control.14  The 
somatotropin remained elevated at the 15 minute and 60 minute intervals.  In humans, multiple 
studies have shown a significant increase in growth hormone following BFR with low resistance 
exercise as compared with high resistance exercise.20,23  In addition to increased growth hormone 
expression, myogenic and proteolytic mRNA expression has been studied in human subjects 
undergoing low resistance BFR exercise.  Interestingly, myogenic mRNA expression is 
unchanged.  However, proteolytic gene (FOXO3A, Atrogin-1, and MuRF-1) expression is 
downregulated as compared to patients without BFR.12,17  Gene expression of myostatin, a 
protein that inhibits myogenesis, was shown to be downregulated in a patient with inclusion 
body myositis after undergoing BFR low resistance exercises.17 
 
Interestingly, one may speculate that muscles proximal to the occlusion cuff may not experience 
similar strength gains as found in those distal to the cuff.  However, a systematic review by 
Dankel et al. (2016) found several instances of proximal gains in muscle size and strength.8  
Suggested mechanisms for this phenomenon include the typical high repetition characteristic of 
BFR exercises (upwards of 75 total repetitions per exercise)8, purported synergistic effects of 
proximal musculature as the distal muscles fatigue3 and higher recruitment of type II muscle  

activation25, and muscle cell swelling occurring during BFR.11  This is important for future 
research of the utilization of BFR with proximal musculature. 
 
What is currently unknown are the potential for improvements in strength of musculature 
proximal to the occluding cuff during BFR training.  The rotator cuff serves as an excellent 
example due to its proximal location to typical UE placement as well as documented EMG 
specificity with certain exercises.4,5,15,16  Any strength gains, if elucidated with given program, 
should be easily detectable.  Data from this study may possibly provide foundational information 
for future studies utilizing similar methods with different populations 
 
The most frequently encountered side effects of BFR training is bruising and muscle soreness at 
the tourniquet site.12,25  BFR exercise does not show increase in markers for muscle damage such 
as myoglobin or creatine kinase.3  Deep vein thrombosis is infrequently seen at a rate of less than 
.1%.12,24  
 
5) Setting of the Human Research  
The research will be conducted in an outpatient physical therapy clinic under close supervision 
of a trained and licensed physical therapist.  Additional locations may include: Rice University 
Campus 6100 Main St. Houston, TX 77005. 
 
6) Resources available to conduct the Human Research  
Equipment required for study will include: Delfi PTS Blood Flow Restriction Tourniquet 
System, MicroFET 2 hand-held dynamometer, cable column machine, free weights, VICON 
motion capture system. 
 
7) Study Design  
Study participants will be randomly allocated in to 3 groups: control group (no exercise), 
exercise group, and BFR + exercise.  Power analysis indicates the need for approximately 20 
individuals in each group.  Each exercise group will perform the same set of exercises 2 
days/week for 8 weeks on their non-dominant upper extremity.  Each group will also undergo 
strength testing at the same time throughout the protocol.  Whereas the control group will only 
undergo testing in the same time periods.  Muscle strength testing will be performed before the 
initiation of the program, at 4 weeks, and upon conclusion of the program.  Testers will be 
blinded to group allocation.  Muscle testing will be performed using manual hand-held 
dynamometry consistent with literature describing appropriate methods.9,18  Each manual muscle 
test will be performed as maximal exertion one repetition maximum test (1RM) three times to 
ensure most accurate dynamometry reading.  For any baseball pitcher participants, motion 
capture measures will be taken before week 1 and after week 8. This will include sensors that 
measure range of motion and arm biomechanics for a maximum of 25 pitches in each session.  
To ensure test-retest reliability, each participant will undergo testing by the same individual.  A 
familiarization protocol will be enforced to ensure all participants are familiar with testing 
measures and to decrease the amount of variability in intratester performance. 
 
Exercises are as follows: 
1. Cable column external rotation (at 90 degrees of abduction) 
2. Cable column internal rotation (at 90 degrees of abduction) 

 
 
3. Sidelying external rotation with weight (0 degrees) 
4. Standing scaption with weight 
• 
These exercises have been found to incorporate the greatest electromyographic 
muscle activity of the rotator cuff in the literature.4,5,15,16 
• 
The order of exercises will remain same for each participant in each group 
 
BFR tourniquet placement will occur at the most proximal portion of the upper extremity.  
Tourniquet pressure will be applied at 50% of maximal limb occlusion pressure, to be re-
measured each week.  This is consistent with current literature recommendations for upper 
extremity BFR training.6,8,13 
 
Resistances for each exercise will be determined by using 10-30% of 1RM (found during 
testing).  This is consistent with current literature recommendations for upper extremity BFR 
training.6,8,13  Resistance may be increased as the subject tolerates so long as they stay within the 
10-30% 1RM range.  Following strength testing at 4 weeks, resistances may be adjusted due to 
strength gains. 
 
a) Recruitment Methods  
Potential study participants will be recruited from the local area who will be able to access clinic 
and equipment.  Participants will be surveyed to ensure all inclusion and exclusion criteria are 
met. 
  
b) Inclusion and Exclusion Criteria  
Inclusion: participants must be healthy, untrained, volunteers who accept all provisions of the 
study and agree to complete the program in its entirety.  Ages accepted will be 18-65. 
Exclusion: potential participants will be excluded if: 
1. Previous history of shoulder injury occurring in the laterality of choice 
2. Current painful dysfunction resulting in exercise limitation 
3. Any health-related exercise limitation as ordered by physician 
4. Vascular compromise or previous vascular surgery 
5. Ages outside of 18-65 
6. Inability to access clinic and equipment 
7. Currently involved in structured strength training regimen of the upper extremity 
 
c) Study Endpoints  
Exercise programs for each individual will terminate upon the completion of 16 sessions over 8 
weeks.  If any subject reports adverse effects (pain, injury, decreased range of motion), their 
program will be terminated and referral given for treatment by physician.  Subject recruitment 
will occur over the course of 6-12 months or until reasonable power is achieved. 
 
d) Procedures involved in the Human Research  
Eligibility will be explained during the consent process with each participant.  Minimal risk will 
be explained to the patient regarding exercise and blood-flow restriction training.   

e) Data management  
The PI will be responsible for all data collected, its confidential storage, and deletion after the 
study is completed. 
 
f) Withdrawal of subjects  
Subjects may withdraw at any time for any reason.  Their data will be included if the individual 
has performed at least 4 weeks of the program.  If the individual withdraws prior to 4 weeks, any 
pre-program testing will be deleted. 
 
8) Risks to subjects  
Minimal risks are present but may include arm pain due to tourniquet pressure or possible deep 
vein thrombosis. 
 
9) Potential benefits to subjects  
Subjects in either group may experience strength gains consistent with a strength-training 
program. 
 
10) Provisions to protect the privacy interests of subjects  
PHI information will not be used or published in the study as all information will be used to form 
aggregate data. The data will be kept on a secure password protected, hospital server and will be 
deleted after the study is complete.  Subject data will be coded according to initial randomized 
group allocation. 
 
11) Provisions to maintain the confidentiality of data  
See #10 
 
12) Cost to subjects  
No costs will be incurred to the subjects. 
 
13) Consent process  
Participants will be educated on the data accrual process when they obtain the inclusion survey.  
Participation is completely voluntary and submission of declaration of inclusion is mandatory to 
be allocated to grouping and undergo testing/exercise program. 
 
14) Process to document consent in writing  
The standard consent form for this project will be explained and if the subject wishes to 
participate the consent will be signed prior to the start of the questionnaire. 
 
 
 
 
 
 
 
 
 

 
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