We will test the efficacy of an innovative physical therapy treatment technique based upon the Lee Silverman Voice Treatment (LSVT). Thus, people with PD will undergo intensive practice of high effort/- large amplitude arm movements while focusing on the sensory awareness of "movement bigness." As LSVT uses extensive practice and feedback/knowledge of results to teach patients the amount of effort needed to consistently perform "louder" voice, we will use similar motor learning techniques to teach patients the amount of effort needed to consistently perform "bigger" movements. Speech studies have shown that a treatment with a simple focus (think loud) may generalize to affect motor output in other systems (e.g., articulation, speaking rate, swallowing, respiratory mechanics). Thus, we predict that learning to perform bigger arm movements will not only improve arm function during everyday activities, but the effects will generalize to lower limb function and speech motor control.