• Distance walked in 6 minutes [ Time Frame: study entry (0 weeks), 7 and 13 weeks ] [ Designated as safety issue: No ]
  

• Unified Parkinson's disease Rating Scale (UPDRS) - motor examination [ Time Frame: 0, 7 and 13 weeks ] [ Designated as safety issue: No ]
  
• The Parkinson's disease Questionnaire (PDQ-39 [ Time Frame: 0, 7 and 13 weeks ] [ Designated as safety issue: No ]
  
• Walking Automaticity, determined as the velocity of walking 10m while performing a concurrent (cognitive or cognitive + physical) task expressed as a percentage of the velocity of walking 10m without performing the concurrent task. [ Time Frame: 0, 7 and 13 weeks ] [ Designated as safety issue: No ]
  
• Walking consistency determined as the co-efficients of variation for stride time and stride length recorded during the 6 minute walk test. [ Time Frame: 0, 7 and 13 weeks ] [ Designated as safety issue: No ]
  

Behavioral: Treadmill training
Walking on a treadmill 3 times per week for 6 weeks

After Alzheimer's disease, Parkinson's disease (PD) is the most common degenerative neurological condition suffered by Australians, with more than 30,000 Australians having PD at any one time (Parkinson's Australia). Hypokinesia, ie, reduced speed and amplitude of movement, is a major impairment of motor control affecting walking in people with PD. Over time, the development of slow, shuffling walking contributes to loss of independence and falls, with devastating consequences for individuals with PD and their families(Ashburn et al, 2001, Playfer 2001). Any decrease or delay in disability will reduce the personal and financial costs to individuals with PD, their families, health care resources and the community.

A number of previous studies suggest exercise capacity and exercise habits are positively correlated. In people with mild Parkinson's disease (Canning et al 2005), walking capacity, measured as distance walked in the 6-min walk test, correlated with the amount of walking (r=.64, p<0.01) performed each week. Similarly, in an earlier study of people with mild to moderate Parkinson's disease, regular exercise was associated with better exercise capacity (Canning et al 1997). It appears, therefore, that proactive intervention aimed at developing good exercise habits in sedentary individuals with early to mid-stage Parkinson's disease has the potential to reduce or delay walking difficulties.

This study aims to establish the efficacy of a home-based treadmill walking program in providing an early intervention which addresses the primary motor control impairment of hypokinesia, while at the same time maintaining or improving exercise capacity.