This clinical trial evaluates whether patients with deep soft tissue sarcomas who receive a tailored prehabilitation exercise regimen during standard radiotherapy and prior to standard of care surgery have better recovery and surgical outcomes than those who do not. Patients undergoing surgery to soft tissue sarcomas are at high risk for post-operative disability, which is associated with high rates of depression and poor health-related quality of life. Prehabilitation is the practice of exercising before surgery to ensure that the patient is in the best possible condition. It allows patients to prepare their bodies for recovery after surgery, which may result in better surgical outcomes, recovery, and quality of life after surgery.