Exercise as it relates to Disease/Power for Parkinson Patients

This is an analysis of the journal article ‘Power training induced change in bradykinesia and muscle power in Parkinson’s disease’ by Ni et. al (2015).

What is the Background to This Research?
Parkinson disease (PD) is a degenerative and progressive brain disease that results in slowness of movement (bradykinesia), trembling, stiffness and the loss of fine motor control. The disease destroys neurons within the brain which produce the neurotransmitter dopamine and therefore gradually reduces and inhibits the ability to control movement.

Coupled with symptoms of PD is muscle weakness across numerous muscle groups in both the upper and lower limbs. The need for resistance training to preserve or delay the reduction in muscle weakness is something that is highly warranted.

The researches in this article wanted to explore if a specific type of resistance exercise in power training, which is a high velocity/low resistance form of exercise that has been shown to be an effective exercise intervention for improving strength, power and performance in healthy older populations could also be beneficial for a PD population.

The importance of these findings would enable a greater specified prescription of activity for PD patients to further the delay of the degenerative effects seen as a result of the disease.

Where is the Research From?
This research was undertaken by staff out of the University Of Miami, Florida between the departments of neuromuscular and active aging laboratory and the centre on aging. Authors have previous publications and research history with exercise interventions in older healthy and diseased adults.

What Kind of Research is This?
This study was a randomised control trail (RCT), which formed part of a larger study that examined the comparative impacts of power resistance training and power yoga on PD patients using a Unified Parkinson’s Disease Rating Scale (UPDRS). Balance, mobility and leg press power and strength were also assessed within this particular study during the 3 month exercise intervention period.

A RCT was the best option for this study as it provides a strong way to determine if a cause-effect relationship exists between the treatment (PWT) and the outcome of improved bradykinesia and muscular performance.

What Did the Research Involve?
The design of this study involved participants being placed in either a power training (PWT) or control group (CON). The CON group were given 1 hour of non-exercise health education classes every 4 weeks and were instructed not to change their current exercise routine over the course of the 3 month study. The PWT group were instructed in 11 exercises on pneumatic machines (10-12reps x 3sets) 2 times per week over 12 weeks. Week 1 was treated as an adaptation period, from weeks 3 onward increases in load occurred based on participants reaching power plateaus. Additionally weeks 5-6 and 11-12 incorporated balance and agility activities which comprised of line, ladder, cone, step, chair and ball drills.

A limitation identified within the methodology is the small sample size of groups which potentially could have reduced the power of detecting further cross-correlations between groups. Secondly measures were not taken on asymmetrical limb strength and power as PD commonly affects one side of the body to a greater extent, this is commonly seen within patients who are in the mild to moderate stage of the disease.

What Were the Basic Results?
The primary outcome measure for this study was limb bradykinesia score. Secondary outcomes identified by researchers included muscle strength and power and participants quality of life.

Main Findings
1: A 3 month PWT program significantly reduced limb bradykinesia score, increased muscular strength and power and improved quality of life.

2: No significant correlation were detected between the changes in limb bradykinesia scores and muscle power.

Interpretation/Explanation of Results
1: Bradykinesia: The PWT group had a significant improvement in both upper and lower limb bradykinesia scores following training compared to the control group. Researchers have postulated that this is due to the neuronal activation enhancement of the basal ganglia region of the brain in which participants are learning to better activate the motor units responsible for activation of specific muscles.

2: Muscle Strength & Power: The PWT produced significant improvements for all 5 of the tested exercises (bicep curl, chest press, leg press, hip abduction and seated calf) following training in muscle strength. Muscle power elicited improvements in 4 of the 5 exercises, the exception being the seated calf.

3: Quality of Life: Significant improvements were reported by the PWT group in mobility, activity of daily living (ADL) and social support. These findings are in line with previous study which used a similar form of resistance exercise that being eccentric resistance training.

What Conclusions Can We Take From This Research?
The results from this study further highlight the positive impact that resistance training in particular power training can have on persons with PD in relation to limb bradykinesia, muscle function and quality of life. Improvements in strength seen in this study for key muscle groups within the lower limbs have also been highlighted as a marker to reduce fall probability, and increase balance and walking speed.

Practical Evidence?
Results from this research provide the greater evidence for health professionals to use a personalised power training program as an exercise strategy that can be incorporated into outpatient care and rehabilitation for PD patients.

Additional/Further Reading
Information sheets on Parkinson's Disease - http://www.parkinsons.org.au/information_sheets

Unified Parkinson's Disease Rating Scale (UPDRS) - http://www.movementdisorders.org/MDS/Education/Rating-Scales.htm