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Effects of 2 Years of Exercise on Gait Impairment in People With Parkinson Disease: The PRET-PD Randomized Trial

Rafferty, Miriam R. PT, DPT, PhD, NCS; Prodoehl, Janey PT, PhD; Robichaud, Julie A. PT, PhD; David, Fabian J. BSPT, PhD; Poon, Cynthia PhD; Goelz, Lisa C. PhD; Vaillancourt, David E. PhD; Kohrt, Wendy M. PhD; Comella, Cynthia L. MD; Corcos, Daniel M. PhD

Journal of Neurologic Physical Therapy: January 2017 - Volume 41 - Issue 1 - p 21–30
doi: 10.1097/NPT.0000000000000163
Research Articles
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Background and Purpose: This study presents a secondary analysis from the Progressive Resistance Exercise Training in Parkinson Disease (PRET-PD) trial investigating the effects of progressive resistance exercise (PRE) and a Parkinson disease (PD)-specific multimodal exercise program, modified Fitness Counts (mFC), on spatial, temporal, and stability-related gait impairments in people with PD.

Methods: Forty-eight people with PD were randomized to participate in PRE or mFC 2 times a week for 24 months; 38 completed the study. Gait velocity, stride length, cadence, and double-support time were measured under 4 walking conditions (off-/on-medication, comfortable/fast speed). Ankle strength was also measured off- and on-medication. Twenty-four healthy controls provided comparison data at one time point.

Results: At 24 months, there were no significant differences between exercise groups. Both groups improved fast gait velocity off-medication, cadence in all conditions, and plantarflexion strength off-/on-medication. Both groups with PD had more gait measures that approximated the healthy controls at 24 months than at baseline. Plantarflexion strength was significantly associated with gait velocity and stride length in people with PD at baseline and 24 months, but changes in strength were not associated with changes in gait.

Discussion and Conclusions: Twenty-four months of PRE and mFC were associated with improved off-medication fast gait velocity and improved cadence in all conditions, which is important because temporal gait measures can be resistant to medications. Spatial and stability-related measures were resistant to long-term improvements, but did not decline over 24 months. Strength gains did not appear to transfer to gait.

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Center for Education in Health Sciences (M.R.R.) and Physical Therapy and Human Movement Science (F.J.D., C.P., D.M.C.), Northwestern University, Chicago, Illinois; Physical Therapy Program, Midwestern University, Downer's Grove, Illinois (J.P.); Department of Rehabilitation Services, University of Illinois Hospital and Health Science System, Chicago (J.A.R.); Department of Kinesiology and Nutrition, University of Illinois at Chicago (L.C.G.); Department of Applied Physiology and Kinesiology, University of Florida, Gainesville (D.E.V.); Division of Geriatric Medicine, University of Colorado School of Medicine, Aurora (W.M.K.); and Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois (C.L.C.).

Correspondence: Miriam R. Rafferty, PT, DPT, PhD, NCS, Center for Education in Health Sciences, Northwestern University, 633 N. St Clair 20th Floor (2024-L), Chicago, IL 60611 (

PRET-PD was funded by grant R01-NS28127-12 to 16 from the National Institute of Neurological Disorders and Stroke. MRR also funded by the Foundation for Physical Therapy, and would also like to acknowledge funding from the University of Illinois at Chicago Graduate College, and National Institute of Mental Health T32 MH067631 Training in the Neuroscience of Mental Health, and by an Advances in Rehabilitation Research Training Grant (Administration for Community Living, NIDILRR grant number H133P130013, PI Allen Heinemann, PhD). These contents do not necessarily represent the policy or endorsement of the funding sources. MRR discloses that she has received honorarium from the National Parkinson Foundation (NPF), the publishers of the Fitness Counts exercise program, for travel and services related to the NPF Quality Improvement Initiative. No other conflicts of interest related to this project are reported by other authors.

Research and training support from the Foundation for Physical Therapy, University of Illinois at Chicago Center for Clinical and Translational Science, National Institute of Mental Health, National Institute of Disability, Independent Living, and Rehabilitation Research (MRR); NIH (JP, JAR, FJD, CP, LCG); NIH, Michael J. Fox, and consults for projects at UT Southwestern Medical Center and Great Lakes NeuroTechnologies (DEV); DoD and consulting fees from the NIH (WMK); research support from Allergan Inc, Merz Pharmaceuticals, Ipsen Limited, NIH, and Parkinson Disease Foundation and consulting fees from Neupathe, Allergan Inc, Merz Pharmaceuticals, Ipsen Limited and Medtronic Corporation (CLC); NIH and Michael J. Fox, and receives lecture and reviewer fees from NIH (Daniel M. Corcos). registration number: NCT00591344.

These data were presented at the Combined Sections Meeting of the American Physical Therapy Association 2014. Las Vegas, Nevada. Other data from this clinical trial, including the full CONSORT diagram, has been published in Corcos et al. Movement Disorders, 2013, and Prodoehl et al. Neurorehabilitation and Neural Repair, 2015.

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