Dose-response characteristics of exercise training in individuals with Parkinson's disease: an exploratory study

Exercise training is often prescribed as an adjunct to medication to improve postural instability in individuals with Parkinson’s disease. As the association between exercise dose and the corresponding effects on postural stability has not been established in this population, we aimed to explore this topic in the present study. This is an exploratory study conducted in the Gait and Balance Laboratory at the Hong Kong Polytechnic University in a period from June 2011 to June 2013. Eligible participants with Parkinson’s disease (n = 51) were randomly assigned to either a balance and gait training group or a strength training group. The 12-week training period included two 4-week phases of physiotherapist-supervised laboratory-based training separated by a 4-week phase of self-supervised home-based training. Blinded testers examined postural stability using the limit of stability test, single-leg-stance test, walking test, and the activities-specific balance confidence scale, at baseline and after each training phase. Baseline evaluations revealed no significant difference between the balance and gait training and strength training groups. In the balance and gait training group, the first 4-week training phase led to significant improvement in most measures of balance and gait performance (P < 0.025), and the 12-week training phase yielded further improvements in gait velocity and activities-specific balance confidence scale score. In the strength training group, the first 4-week training phase led to significant improvement in the endpoint excursion in the limit of stability test and gait velocity, and the 12-week training phase resulted in an improvement in the single-leg-stance time and stride length in the walking test. All improvements occurred during the laboratory-based training sessions. Therefore, in individuals with Parkinson’s disease, a 4-week period of balance and gait training could improve postural stability, whereas longer durations of strength training are required to gain comparable improvements.