Effects of Muscle Cooling on Motor Unit Firing of the Quadriceps

The overall objective of this pilot study is to establish the feasibility and methodological validity of using high-density surface electromyography to characterize motor unit behavior of the quadriceps under thermoneutral and locally cooled conditions, and to generate preliminary data to inform the design of a larger, hypothesis-driven study.

Inclusion Criteria: * Men and women between the ages of 18 and 35 years * Healthy adults, defined as absence of significant acute/chronic medical condition, injury, and/or illness that may compromise subject safety, limit the ability of the participant to complete the study, and/or compromise the objectives of the study as determined by the Principal Investigator. Exclusion Criteria: * Current diagnosis or history of: * major metabolic disease (e.g., type I and type II diabetes), * neuromuscular disease (e.g., cervical spondylotic radiculomyelopathy, lumbar spondylosis, amyotrophic lateral sclerosis, Guillain-Barré syndrome, and acquired demyelinating polyneuropathies), * cardiovascular disease (e.g., stage II hypertension, heart failure, myocardial infarction/ischemia, peripheral vascular disease, Raynaud's phenomenon, or other conditions associated with impaired peripheral circulation), * significant myocardial or pericardial diseases (e.g. amyloidosis, constriction), * moderate or severe valvular disease, * pulmonary/respiratory disease (e.g., asthma, chronic bronchitis, emphysema, chronic obstructive pulmonary disease), * cancer, * renal disease, * liver disease, * or anemia. * Current or recent musculoskeletal injury (e.g. fracture, sprain, dislocation) or any physical disability that precludes safe and adequate testing. * Pregnancy or breastfeeding. * Thigh circumference greater than 23 inches * Mid-thigh skinfold thickness greater 40 mm