BDNF and Parkinson disease: The specific aims of the present paper are to: (1) investigate the immediate and long-term effects of NW exercise on walking function, motor/non-motor PD symptoms, and BDNF levels in persons with mild to moderate idiopathic PD, (2) determine the feasibility of implementing an individualized, progressive NW exercise program, and (3) examine independent NW exercise engagement after a supervised training program to assess feasibility and sustainability of this mode of task-specific aerobic exercise.