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 History of arthritis Use of an assistive walking device or mobility aids within the past six months Use of anabolic steroids within the past six months History of convulsions, seizures, or syncope History of concussion as diagnosed by a physician Certain medications (e.g., muscle relaxants, benzodiazepines) Very thick hair or certain hairstyles that would impede the TMS coil from making direct contact with the scalp Allergy to rubbing alcohol Lack of transportation to and from the laboratory Implant of any kind Pregnancy Allergy to silver Diagnosis of any psychiatric condition