Short-term Immobilization and Rehabilitation of the Lower Limb: Changes in Strength, Size, and Neuromuscular Function
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Weakness, Muscle
- Sponsor
- University of Central Florida
- Enrollment
- 50
- Locations
- 1
- Primary Endpoint
- Muscular size
- Status
- Completed
- Last Updated
- 3 years ago
Overview
Brief Summary
The purpose of this study is to determine the effects of one week of knee-joint immobilization on muscle size, strength, neuromuscular function, and brain function. In addition, the effects of two different interventions (i.e., neuromuscular electrical stimulation and action observation/mental imagery) throughout immobilization will be determined. Following the immobilization period, participants that have lost strength will be rehabilitated with twice weekly resistance training sessions, and sex-based differences in rehabilitation timelines will be examined.
Detailed Description
This study will utilize a repeated measures design in healthy adults aged 18-40 years. After a thorough familiarization visit, muscular size, strength, neuromuscular responses, and corticospinal excitability/inhibition will be measured before (PRE) and after (POST) one week of unilateral knee joint immobilization of the left leg. Four groups will be examined: 1) immobilization only, 2) immobilization + daily neuromuscular electrical stimulation, 3) immobilization + daily action observation/mental imagery training, 4) a control group. Throughout the immobilization period, participants will be in a leg brace locked at 90 degrees knee flexion. They will perform daily range of motion exercises and wear a compression sock at all times to mitigate the risk of blood clots. Following completion of the immobilization period, participants that have lost strength will complete a supervised rehabilitation program of twice weekly lower body resistance training sessions until they have returned to baseline levels of strength. Group assignment will be randomized and blocked on sex to ensure an equal number of participants within each group consisting of a relatively equal number of males and females.
Investigators
Matt Stock
Associate Professor of Physical Therapy
University of Central Florida
Eligibility Criteria
Inclusion Criteria
- •Healthy men and women between the ages of 18-40 years
- •Body mass index \>20 kg/m2 or \< 35 kg/m2
Exclusion Criteria
- •Body mass index \<20 kg/m2 or \> 35 c
- •Experience of major joint pain/discomfort of the upper or lower limbs, back, or neck within the previous six months.
- •History of major musculoskeletal injury or surgery
- •Neuromuscular disease (e.g., Parkinson's, MS, ALS)
- •Metabolic disease (e.g., diabetes, thyroid disorder, metabolic syndrome)
- •Personal or family history of blood clots
- •Trouble using or controlling one's muscles
- •History of cancer
- •History of stroke
- •History of heart attack
Outcomes
Primary Outcomes
Muscular size
Time Frame: 10 minutes
Changes in muscular size will be measured via ultrasonography of the quadriceps
Voluntary activation
Time Frame: 15 minutes
Voluntary activation will be measured using the interpolated twitch technique
Rate of recovery
Time Frame: 1.5 hours per session
The time taken to recover strength lost will be measured via number of resistance training sessions needed after immobilization
Muscular strength
Time Frame: 15 minutes
Changes in muscular strength will be measured via maximal voluntary contraction torque
Corticospinal responses
Time Frame: 30 minutes
Corticospinal responses will be measured with transcranial magnetic stimulation targeting the lower limbs
Motor unit behavior
Time Frame: 10 minutes
Motor unit recruitment threshold and firing rate will be measured with surface electromyography signals detected from the quadriceps
Secondary Outcomes
- Compliance(one week)
- Physical activity (Step count)(one week)