LSVT BIG is an intensive, amplitude based rehabilitation program that has been demonstrated to improve one of the hallmark features of Parkinson's disease, specifically bradykinesia. We are interested in knowing the effects of this therapeutic approach on postural control and gait parameters.

LSVT BIG is an intensive, amplitude based rehabilitation program that has been demonstrated to improve one of the hallmark features of Parkinson's disease, specifically bradykinesia. Postural instability and gait disturbance is another debilitating feature of Parkinson's disease. While LSVT BIG targets postural correction through exercises which challenge balance, the effect of this intervention on stability margins and functional balance assessments have not been well established in the literature. This study includes outcome measures not previously examined with this intervention and may provide valuable evidence regarding the impact of this intervention on postural control, balance and falls risk. Alternative amplitude programs have also been designed to meet the needs of patients with PD. These programs adjust frequencies for patients and individualize sessions more than LSVT BIG. We are interested in knowing if these alternative frequencies and amplitude approaches are similarly as effective as LSVT BIG in our outcome measures.

Inclusion Criteria:

• Subjects will be included in the study if they have been diagnosed with idiopathic Parkinson's disease and are English speaking.

Exclusion Criteria:

• Exclusion Criteria: 1) previous completion of LSVT BIG or other formal amplitude program training 2) non-idopathic Parkinsonism 3) any medical condition that would contraindicate exercise (ie. unstable cardiovascular disease) 4) cognitive impairment that limits ability to follow direction or demonstration