Training Induced Muscle Exosome Release

Inclusion Criteria: * 18-30 years of age. * Either BMI \<25 or \>30. * Relatively sedentary, reporting no participation in regular (\>1 day per week) exercise for at least the past 3 months. * Non-smoker. Exclusion Criteria: * BMI between 25 and 30. * Evidence or signs and symptoms for cardiovascular disease (previous heart attack, arrhythmias, angina, shortness of breath, extreme fatigue, unusual pain in neck, jaw, throat, upper abdomen, or back, swelling in feet, legs, or ankles). * Evidence or signs and symptoms of metabolic syndrome or disorder (diagnosis of diabetes or insulin resistance, elevated BP, high fasting blood sugar, abnormal cholesterol or triglyceride levels). * Chronic aspirin or NSAID use (unless it can be safely stopped prior to the biopsies), and any other use of an anticoagulant (e.g., Coumadin) or history of bleeding including history of hypo- or hyper-coagulation disorders. * Neurological, musculoskeletal, or other disorder that would preclude safe participation in the weight lifting tasks and all performance tests. * Any other medical condition that would interfere with testing or increase one's risk of complications during exercise, as judged by the study physician. * Any other condition or events considered exclusionary by the PI and/or physician, such as non-compliance. * Lidocaine allergy (1% lidocaine is the local anesthetic used during the muscle biopsy procedure). * Pregnancy.