Muscle Atrophy
Conditions
Brief summary
Patients in rehabilitation may undergo periods of prolonged limb immobilization in response to injury, surgery, or illness. Due to disuse, the size and strength of muscles controlling the affected limb can decrease significantly, possibly resulting in physical impairment or lower quality of life during the recovery phase. Prior immobilization studies have shown that the rate and degree of decline in muscle strength exceeds that of muscle size, indicating that determinants of muscle strength unrelated to muscle size may further contribute to functional changes during immobilization. The purpose of this study is to describe the changes in muscle strength, muscle size, corticospinal excitability, voluntary activation, M1 cortical thickness, and resting state functional connectivity following a 2-week limb immobilization period in young women.
Interventions
BEHAVIORALImmobilization
Immobilization of left arm using a brace and sling.
Sponsors
McGill University
Study design
Allocation
NON_RANDOMIZED
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* Biologically female * Right-hand dominant * Body mass index between 18.5-30 kg/m\^2 (inclusive) * Regular menstrual cycle * Be able to maintain a habitual diet throughout the duration of the study
Exclusion criteria
* Use of tobacco * Pregnancy * A history of brain trauma * Suffers from a neurological disease or movement disorder * Peripheral nerve damage * Use of medications known to affect protein metabolism (i.e., corticosteroids, non-steroidal anti-inflammatory drugs, or prescription strength acne medications) * Diagnosed with or suspects having a psychiatric illness * Use of dietary supplements known to affect muscle size (i.e., creatine, fish oil) * Past or present diagnosis of an eating disorder by a physician or registered dietician * Possesses any metal implants (e.g. artificial joints, pacemakers, stents) or non-removeable medical devices that are contraindicative for magnetic resonance imaging (e.g. insulin pumps)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in corticospinal excitability of biceps brachii, both arms | Comparison between before immobilization and 24 hours of left arm immobilization, and before and after 2 weeks of left arm immobilization | Measured using transcranial magnetic stimulation; estimation of the efficacy of the corticospinal tract to relay electrical signals to the biceps brachii muscle |
| Change in isometric elbow flexion and extension peak torque, both arms | Comparison between before and after 2 weeks of left arm immobilization | Measured using an isokinetic dynamometer; peak torque during static contraction of the elbow flexors and extensors |
| Change in isokinetic elbow flexion and extension peak torque, both arms | Comparison between before and after 2 weeks of left arm immobilization | Measured using an isokinetic dynamometer; peak torque during dynamic contraction of the elbow flexors and extensors |
| Change in cross-sectional area of the elbow flexor and extensor muscles, both arms | Comparison between before and after 2 weeks of left arm immobilization | Obtained from magnetic resonance images of each arm |
| Change in volume of the elbow flexor and extensor muscles, both arms | Comparison between before and after 2 weeks of left arm immobilization | Obtained from magnetic resonance images of each arm |
| Voluntary activation of biceps brachii, both arms | Comparison between before and after 2 weeks of left arm immobilization | Measured using peripheral nerve stimulation and an isokinetic dynamometer; estimation of the capacity to voluntarily activate the force-generating elements of the biceps brachii during maximal effort elbow flexion |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in right and left primary motor cortex thickness | Comparison between before and after 2 weeks of left arm immobilization | Obtained from magnetic resonance image of the brain |
| Change in whole brain resting state functional connectivity | Comparison between before and after 2 weeks of left arm immobilization | Obtained from magnetic resonance image of the brain |
Other
| Measure | Time frame | Description |
|---|---|---|
| 2-day caloric and macronutrient intake, during immobilization | Measured during the last 2 days of left arm immobilization | Obtained using self-reported dietary intake records |
| Ovarian hormone concentrations (estradiol, progesterone) | Measured on day of left arm immobilization, before putting on the arm brace | Obtained using blood samples |
| 2-day caloric and macronutrient intake, before immobilization | Measured during the 2-day period right before left arm immobilization | Obtained using self-reported dietary intake records |
Countries
Canada
Outcome results
None listed