Exercise Intervention for Pts With Metastatic Castration-Resistant Prostate Cancer Receiving Abiraterone or Enzalutamide

Inclusion Criteria: 1. ≥18 years of age 2. Metastatic disease that has progressed despite castrate levels of testosterone (surgically or medically castrated, with testosterone levels of \< 50 ng/dL) 3. No prior chemotherapy 4. Initiated therapy with either abiraterone plus a glucocorticoid or enzalutamide within the 3 months prior to randomization 5. Ability to engage safely in moderate exercise as determined by their treating physician 6. Not previously engaged in regular exercise training (\>1-2 d/wk for \> 30 min/d) in the past 6 months 7. Be able to speak and read English Exclusion Criteria: 1. Any condition that causes severe pain with exertion 2. History of bone fractures 3. Active cardiovascular disease including any of the following: * New York Heart Association (NYHA) Grade II or greater congestive heart failure * History of myocardial infarction or unstable angina within 6 months prior to Day 1 * History of stroke or transient ischemic attack within 6 months prior to Day 1 4. Acute or chronic respiratory disease 5. Acute or chronic bone/joint/muscular abnormalities compromising their ability to exercise 6. Neurological conditions that affect balance and, or muscle strength 7. Dementia, altered mental status or any psychiatric condition prohibiting the understanding or rendering of informed consent