To test the strength and physical performance outcomes of a 12-week progressive resistance training (PRT) exercise program in a small cohort of patients with Class III obesity who are preparing for bariatric weight loss surgery at Beth Israel Deaconess. The study will also test patient compliance to the 12 week PRT program. Whereas PRT exercise is currently recommended as a part of preoperative clinical care for bariatric surgery patients, little research has been done to measure the acceptance and effectiveness of a standardized PRT exercise protocol for improving health and perioperative care. Preliminary data from this study could be used to justify larger studies and further investigation.