One of the most common reasons for premature death in PD is falls. Several meta-analyses have concluded that exercise training programs focused on balance and/or strength training are effective at improving aspects of balance. Taken together, the current body of evidence suggests that exercise may be neuroprotective and balance/strength training may decrease the likelihood of a fall. The combination of these efficacious treatment modalities (exercise and balance/strength training) in a comprehensive treatment approach to improve PD symptoms and balance has been previously reported at relatively mild or moderate exercise intensities. Because recent research has suggested that patients with PD may benefit more from more physically intense programs, we are proposing a more aggressive approach with regard to exercise intensity and frequency in the present trial. The primary purpose of this study is to determine the feasibility and safety of a high intensity exercise approach to PD. A secondary purpose is to determine the trajectory of change in outcomes over the duration of the trial from a high intensity fall prevention program. It is hoped that a signal of efficacy will allow this trial to progress to a comparative effectiveness trial. An important innovative design element is collecting biological assays to better understand the mechanism underlying the anticipated clinical improvements.