The Effect of Oral Carnitine Supplementation on MRS-derived Mitochondrial Function

Inclusion Criteria: * Age: 60-80 years * Moderately Overweight: BMI - 25.0 - 35.4 * Sedentary - exercise ≤ 1 day/week * Fasting plasma glucose: \> 100 - \< 126 mg/dL * Readings from two separate days Exclusion Criteria: * Orthopedic limitations, musculoskeletal disease and/or injury * Allergic to xylocaine * Inability to give blood continuously through an intravenous catheter * Have a confounding medical condition that is progressive and unstable such as HIV, Hepatitis C, active cancer, and/or taking medications for those conditions that are likely to confound the assessment of pre-diabetes * Prior surgical operation within the past 6 months * Prior injury to the eye involving metallic objects or fragments * Prior injury involving a metallic object or foreign body (eg. BB, bullet, shrapnel, etc.) * Tattoos from the waist down to the feet * Any of the following implants or devices * Aneurysm clip * Cardiac pacemaker * Implanted cardioverter defibrillator (ICD) * Electronic implant or device * Magnetically activated implant or device * Neurostimulation system * Spinal cord stimulator * Internal electrodes or wires * Bone growth/bone fusion stimulator * Cochlear, otologic or other ear implant * Insulin or other infusion pump * Implanted drug infusion device * Eye implants * Vascular access port and/or catheter * Wire mesh implant or stent * Other implant * Claustrophobia * Prior knee replacement surgery * Pregnant or intending to become pregnant during the study