Inclusion Criteria:

1. Presence of idiopathic PD according to UK brain bank criteria 
2. Age 50-80 years 
3. Presence of Unified Parkinson’s Disease Rating Scale (UPDRS) walking and freezing score ≥1 during medication-on state
4. Stable dose of PD medication for 4 weeks prior to the study
5. Absence of dementia, defined by Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV criteria, (7) no regular use of assistance gait device such as walker or cane 
6. No prominent dyskinesia (UPDRS dyskinesia score > 1) 
7. No on/off fluctuations throughout day 
8. No frequent falls (UPDRS fall score > 1), no significant postural instability (UPDRS postural stability score > 2), and
9. No freezing leading to falls that would affect subjects’ safety or compliance with protocol.

Exclusion Criteria:

1. A candidate will be excluded if they have:
2. Recent history of unstable heart or lung disease 
3. Evidence of pregnancy, uncontrolled psychiatric illness, major neurological condition other than PD (e.g., stroke)
4. Musculoskeletal (e.g., rheumatoid arthritis) or metabolic problems (e.g., diabetes)
5. A candidate will also be excluded if they have recently participated in any other study involving exercise to improve gait or posture