Neurophysiology of Weakness and Exercise in Rotator Cuff Tendinopathy

Study Overview
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Brief Summary
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The purpose of this study is to examine deficits in activation and motor patterns, as well as central drive in patients with rotator cuff tendinopathy. There are three specific aims: (1) determine the effect of acute pain relief on rotator cuff muscle activation in patients with rotator cuff tendinopathy, (2) determine the effect of exercise on rotator cuff muscle activation in patients with rotator cuff tendinopathy, and (3) compare rotator cuff muscle activation between patients with rotator cuff tendinopathy and healthy controls.

Detailed Description
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The long-term goal of our research agenda is to identify the mechanisms associated with rotator cuff tendinopathy (impingement syndrome) and subsequently evaluate novel treatment strategies that address these mechanisms. The objectives of this application are to study the muscle patterns in patients with rotator cuff tendinopathy as well as the effects of both pain and exercise on these patterns. Our first hypothesis is that pain relief from a shoulder injection will result in increased rotator cuff activity. Our second hypothesis is that patients with tendinopathy will demonstrate improved rotator cuff muscle activity following a six-week exercise program and that this improvement will be higher in patients that respond favorably to treatment. Our final hypothesis is that patients with cuff tendinopathy will show decreased rotator cuff activity compared to healthy subjects. The investigators plan on addressing these hypotheses using several novel techniques for muscle activity assessment.

Official Title
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Neurophysiology of Weakness and Exercise in Rotator Cuff Tendinopathy

Conditions
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Muscle Weakness, Acute Pain, Atrophic, Goals, Impairment, Infiltration, Injury, Pain, Pathology, Shoulder Pain, Syndrome, Tendinopathy

Intervention / Treatment
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* Procedure: Subacromial injection
* Other: Physical Therapy


Participation Criteria
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Eligibility Criteria
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Patient Inclusion Criteria: pain with passive provocative maneuvers (positive Hawkins or Neer test) pain with active elevation (positive painful arc) pain with isometric resisted movements (Jobe's empty can test or resisted shoulder external rotation with the arm at the side) demonstrate weakness (>10% force deficit in external rotation) Patient Exclusion Criteria: shoulder surgery on the symptomatic side positive Spurling test traumatic shoulder dislocation or instability in the past 3 months reproduction of shoulder pain with active or passive cervical range of motion signs of rotator cuff tear (drop-arm test, lag signs, gross external rotation weakness, or positive image findings) current musculoskeletal, neurologic or cardiovascular compromise Control Inclusion Criteria: no current or previous shoulder injury matched for age (within 5 years) and sex meet Patient Exclusion Criteria (minus musculoskeletal, neurologic, or cardiovascular compromise) Control Exclusion Criteria: pain with active arm elevation positive Hawkins, Neer, or Jobe's test

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Patients<br>Subjects with shoulder tendinopathy who will undergo both a subacromial injection and physical therapy | Procedure: Subacromial injection<br>* A subacromial injection consisting up 6 cc 0.5% Marcaine with Epinephrine and 1 cc DepoMedrol will be administered.<br>Other: Physical Therapy<br>* A standardized six-week exercise protocol supervised by a physical therapist<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rotator cuff activation after subacromial injection and exercise intervention, difference in rotator cuff voluntary activation between subjects and controls | Assessed using voluntary activation | 6 weeks | 
| Rotator cuff activation after subacromial injection and exercise intervention, difference in specific rotator cuff muscle activation between subjects and controls | Assessed using electromyography (EMG) | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rotator cuff voluntary activation after subacromial injection | Assessed using voluntary activation | 2 hours | 
| Rotator cuff muscle activation after subacromial injection | Assessed using EMG | 2 hours | 
| Rotator cuff voluntary activation correlations with pain levels | Assessed using voluntary activation relative to self-reported pain level | 2 hours | 
| Rotator cuff activation correlations with pain levels | Assessed using EMG relative to self-reported pain level | 2 hours | 
| Rotator cuff voluntary activation after 6-week exercise intervention and subacromial injection | Assessed using voluntary activation | 6 weeks | 
| Rotator cuff muscle activation after 6-week exercise intervention and subacromial injection | Assessed using EMG | 6 weeks | 
| Rotator cuff voluntary activation correlation with improvements in pain relief | Assessed using voluntary activation relative to self-reported pain relief | 6 weeks | 
| Rotator cuff voluntary activation correlation with improvements in clinical outcome measures | Assessed using voluntary activation relative to changes in questionnaire scores | 6 weeks | 
| Rotator cuff muscle activation correlation with improvements in pain relief | Assessed using EMG relative to self-reported pain relief | 6 weeks | 
| Rotator cuff muscle activation correlation with improvements in clinical outcome measures | Assessed using EMG relative to changes in questionnaire scores | 6 weeks | 
| Prior to treatment, rotator cuff voluntary activation in patients relative to healthy controls | Assessed using voluntary activation | 6 weeks | 
| Prior to treatment, rotator cuff muscle activation in patients relative to healthy controls | Assessed using EMG | 6 weeks | 
| After both a subacromial injection and a six-week exercise program, differences in rotator cuff voluntary activation between patients and healthy controls | Assessed using voluntary activation | 6 weeks | 
| After both a subacromial injection and a six-week exercise program, differences in rotator cuff muscle activation between patients and healthy controls | Assessed using EMG | 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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muscle, relating to nervous system, research, rotator cuff, shoulder, staging, strength training, success, systematic review, techniques, testing, time, training, treatment strategy, United States, work, address, atrophic, base, clinical, cost, data, disability, effectiveness, attention, biofeedback, electrical stimulation, electromyography, exercise, exertion, health care service utilization, improved, injection of therapeutic agent, innovation, intervention, knowledge, local anesthetics, measures, modeling, motor, motor control, neuroadaptation, neurophysiology, novel, outcome, outcome measure, pain inhibition, patients, pattern, programs, public health relevance, rehabilitation strategy, reporting