Progressive resistance exercise improves strength and physical performance in people with mild to moderate Parkinson's disease: a systematic review.

QUESTION Does progressive resistance exercise improve strength and measures of physical performance in people with Parkinson's disease? DESIGN Systematic review with meta-analysis of randomised and quasi-randomised controlled trials. PARTICIPANTS People with Parkinson's disease, regardless of gender or level of disability. INTERVENTION Progressive resistance exercise, defined as involving repetitive, strong, or effortful muscle contractions and progression of load as the participant's abilities changed. OUTCOME MEASURES Measures of muscle strength (maximum voluntary force production) - either continuous (force, torque, work, EMG) or ordinal (manual muscle test) - and physical performance measures: sit-to-stand time, fast and comfortable walking speeds, 6-min walk test, stair descent and ascent, the Activities-specific Balance Confidence scale, Timed Up and Go test, and the Short Physical Performance Battery. RESULTS Four (quasi-) randomised trials were included, three of which reported data that could be pooled in a meta-analysis. Progressive resistance exercise increased strength, with a standardised mean difference 0.50 (95% CI 0.05 to 0.95), and had a clinically worthwhile effect on walking capacity, with a mean difference of 96 metres (95% CI 40 to 152) among people with mild to moderate Parkinson's disease. However, most physical performance outcomes did not show clinically worthwhile improvement after progressive resistance exercise. CONCLUSION This review suggests that progressive resistance exercise can be effective and worthwhile in people with mild to moderate Parkinson's disease, but carryover of benefit does not occur for all measures of physical performance. The current evidence suggests that progressive resistance training should be implemented in Parkinson's disease rehabilitation, particularly when the aim is to improve walking capacity.