Endurance Exercise & Virtual Reality for Optimizing Cortical Excitability and Neuroplasticity in PD

Inclusion Criteria: 1. Diagnosis of idiopathic PD (ages 18 -85) in Hoehn and Yahr stages 2 - 3. 2. Subjects need to demonstrate a score of equal to or greater than 23 on the Mini Mental State Examination. 3. Subjects who have a score of ≤21.5 on the Mini Balance Evaluations Systems Test (miniBESTest). Exclusion Criteria: 1. Subjects with a history of other neurological diseases (i.e., stroke, multiple sclerosis). 2. Subjects with a history of severe cardiopulmonary disease, uncontrolled hypertension, orthostatic hypotension, uncontrolled diabetes, severe osteoporosis, severe arthritis affecting their lower extremity joints. 3. Subjects with a history of PD-specific surgical procedures such as deep brain stimulation etc. 4. Subjects with a history of head injury. 5. Subjects with a history of seizures or epilepsy. 6. Subjects who are currently pregnant. 7. Individuals who use of medications that could alter corticomotor excitability or increase risk of seizure. 8. Individuals with skull abnormalities, fractures or unexplained, recurring headaches.