Exercise as it relates to Disease/Exercise and Parkinson's Disease: Improving Gait Speed, Strength and Fitness
This fact sheet summarises, discusses and critiques the research study, "Randomized Clinical Trial of 3 Types of Physical Exercise for Patients With Parkinson Disease". 
What Is The Background To This Research?
Parkinson’s Disease is a progressive, degenerative neurological condition, that affects the movement function, motor skills and cognitive function of an individual. The onset of symptoms are caused by the deterioration of cells in the substantia nigra (located in the basal ganglia), leading to a decline in the production of dopamine, which usually assists in movement regulation, causing motor and non-motor symptoms.
|Motor Symptoms||Non-Motor Symptoms|
|Resting Tremor||Mood Disorders|
|Postural Instability||Cognitive Impairment|
|Gait Impairments||Sleep Problems|
The study compared the effect of exercise interventions on gait speed, muscle strength and cardiovascular fitness of individuals with Parkinson’s Disease. It was conducted to evaluate previous research in this area with larger sample sizes and minimization of previous limitations, such as un-blinded data collection. With the arms of the study being active comparators, the clinical trial didn't compare exercise against no exercise, although previous research shows that exercise improves motor control and physical functioning.
There is no known cure for Parkinson’s Disease and the extent of the treatment options include medicinal and surgical therapy. With Parkinson's Disease affecting over 70,000 Australians and 32 new cases being diagnosed everyday, it is important to determine the effectiveness of interventions, such as exercise, in addition to current treatments or as a non-invasive alternative.
Where Is The Research From?
The study was completed at the Parkinson's Disease and Movement Disorders Center at the University of Maryland (Department of Neurology, Medicine, Psychiatry & Nursing), and the Baltimore Veterans Affairs Medical Center, Geriatric Research Education and Clinical Centre (Division of Gerontology and Geriatric Medicine).
Dr. Shulman is an established scholar within the research scope of Parkinson’s Disease, and is program director of the University of Maryland Parkinson’s Disease & Movement Disorder Center. She has six publications as lead author in this area, none of which focused on exercise.  The study was funded by the Michael J. Fox Foundation (disclosed in the literature), as well as conflicts of interest regarding research funding for the authors.
What Kind Of Research Was This?
The study was a comparative, prospective, randomised, single-blinded clinical trial of individual's with Parkinson's Disease. Despite the study being blinded for data collection, the unavoidable un-blinding of participants (often seen in exercise studies) could be a limitation of the study as it increases participants bias. 
What Did The Research Involve?
The study involved 67 participants with Parkinson’s Disease (stage 1-3 on the Hoehn and Yahr stage scale, 2-3 cardinal signs, and mild to moderate gait impairment), which were randomly allocated into the exercise intervention groups. These include;
|Lower Intensity Training||Treadmill, 0% incline, 50 minutes. 40-50% HRR.|
|Higher Intensity Training||Treadmill, 0% incline, 30 minutes 70-80% HRR.|
|Stretching and Resistance||2 sets x 10 repetitions. Leg Press, Leg Extension, Leg Curl.|
36 exercise sessions were completed (3 x week for 3 months.)
The results were determined using the outcome measures at the end of the clinical trial, which include:
- 6-minute walk (gait speed)
- Vo2 max (cardiovascular fitness)
- 1 repetition maximal strength (muscular strength)
What Were The Basic Results?
Descriptive statistics were used to determine the variables between the exercise groups. At the conclusion of the trial, all exercise groups improved in 6-minute walk (gait speed). Greater differences were seen between muscle strengthening and cardiovascular fitness.
- Gait speed - 12% and 9% increase respectively in lower intensity training and stretching & resistance. Higher intensity increased by 6%. Lower intensity training had the most consistent improvements in gait speed.
- Strength - increased in all exercise groups, most significantly in stretching and resistance (16%). The other groups did not display significant changes.
- Cardiovascular fitness - improved significantly in lower intensity (7%) and higher intensity (8%) groups. Cardiovascular fitness in stretching and resistance decreased (-0.2%).
The authors acknowledged, as have previous studies, that the future direction of research needed to incorporate longer trial periods to determine the impact of exercise long term. The results were presented without correction for multiple comparisons, increasing the chance of type 2 errors.
What Conclusions Can We Take From This Research?
- The study didn’t identify superiority between outcome measurements of lower and higher intensity training, but found the most consistent gait improvements with the lower-intensity exercise. Increased intensity in exercises showed a decrease in gait biomechanics and efficiency, determining that an increase in intensity was not required to achieve benefits. Lower intensity exercise is more practical and feasible for individuals with Parkinson's, as well as being associated with less risk.
- In a study by Pohl et al, it looked at the effect of 30 minutes of high and low speed treadmill training, finding that both trainings resulted in similar improvements in gait speed, similar to that of this study.
- Different outcomes between treadmill and stretching and resistance training interventions suggest the ability for these two exercise groups to be utilised in conjunction with each other to provide maximal results across measures, including gait speed and muscular strength.Further research into these areas would strengthen the evidence resulted from the study. Research regarding the ideal intensity for Parkinson’s Disease, would assist in implementing more beneficial exercise prescription.
- Individual’s with Parkinson’s would benefit from completing lower-intensity exercise training for 50 - 60 minutes, 3 times a week, at a heart rate reserve of 40-50%, inclusive of walking, outside or on a treadmill.
- Capable individuals would benefit from both lower-intensity and stretching and resistance training, as the exercises result in different improvements; being cardiovascular fitness and muscle strength respectively, as well as improving gait speed.
- It is important to understand that the symptoms of Parkinson’s Disease differ among each individual, therefore the capabilities of each individual will differentiate. Before undertaking exercise, it is advised that individuals diagnosed with Parkinson’s Disease speak to their specialist regarding recommendations and limitations.
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