Brain and Muscle Plasticity During Immobilization

Examining Changes in Muscle Size and Strength, Neuromuscular Function, and Brain Plasticity During Limb Immobilization in Women

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.

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)