Strength Training Augmenting Rehabilitation

Study Overview
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Brief Summary
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This project aims to determine whether a novel strength training rehabilitation protocol can diminish the negative consequences of limb immobilization and expedite the restoration of muscle function during retraining in healthy individuals.

Detailed Description
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The present study will examine the time course of muscle strength and size adaptations in two groups of volunteers during immobilization and retraining. Both groups will undergo temporary muscle disuse by wearing a shoulder sling and swathe on their non-dominant arm for  ≥10 hours/day for four weeks. One group (immobilization + unilateral training) will perform progressive unilateral strength training of the free limb throughout the immobilization period. The other group (immobilization control) will not undergo any training during the immobilization period. Following immobilization, both groups will undergo four weeks of bilateral strength training to retrain the immobilized arm.

Official Title
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Strength Training Augmenting Rehabilitation - 1

Conditions
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Muscle Disuse Atrophy

Intervention / Treatment
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* Procedure: Orthopedic immobilization
* Other: Unilateral resistance training
* Other: Bilateral resistance training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: a body mass index between 18 - 35 kg/m2 18-35 years of age right-hand dominant willingness to comply with the immobilization requirements willingness to refrain from strength training outside of the study willingness to comply with the strength training procedures of the study Exclusion Criteria: a personal or family history of blood clots a personal or family history of thyroid disorders previous orthopedic surgeries to the upper limbs and/or joint pain of the upper limbs in the last 6 months neuromuscular or metabolic disorders osteoarthritis use of hormone replacement therapy (ie., testosterone, estrogen, and/or growth hormone pharmaceuticals) pregnancy and/or nursing

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Immobilization control<br>The immobilization control group will undergo arm immobilization. Immobilization will be implemented with four weeks of muscle unloading with a sling and swathe on the nondominant arm. The sling will suspend the arm at the elbow joint with the elbow in a flexed position at 90°, the swathe will then wrap around the participant to fix the arm against the body. | Procedure: Orthopedic immobilization<br>* Orthopedic immobilization will be performed with a sling and swathe.<br>Other: Bilateral resistance training<br>* Bilateral resistance training will be performed by both arms in both groups during Phase 2.<br>|
| Experimental: Immobilization with unilateral training<br>The immobilization with unilateral training group will undergo arm immobilization for four with a sling and swathe on the nondominant arm. The sling will suspend the arm at the elbow joint with the elbow in a flexed position at 90°, the swathe will then wrap around the participant to fix the arm against the body. The free (non-immobilzed) arm of this group will undergo heavy strength training twice per week throughout the immobilization period. The training will consist of unilateral dumbbell shoulder press and biceps curl. | Procedure: Orthopedic immobilization<br>* Orthopedic immobilization will be performed with a sling and swathe.<br>Other: Unilateral resistance training<br>* Unilateral resistance training will be performed by the dominant arm of the immobilization + unilateral resistance training group during Phase 1.<br>Other: Bilateral resistance training<br>* Bilateral resistance training will be performed by both arms in both groups during Phase 2.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in isometric muscle strength | MVC (Newton) | Changes from baseline at 5 and 10 weeks | 
| Changes in dynamic muscle strength | 1RM (lbs) | Changes from baseline at 5 and 10 weeks | 
| Changes in muscle size | Ultrasound muscle thickness of biceps brachii and triceps brachii | Changes from baseline at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 weeks | 
| Changes in lean mass | DEXA | Changes from baseline at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 weeks | 
| Changes in EMG amplitude | Surface EMG | Changes from baseline at 5 and 10 weeks | 
| Changes in action potential amplitude | Surface EMG Decomposition | Changes from baseline at 5 and 10 weeks |