Is there a benefit to power assist wheelchair use? Algood SD, Cooper RA, Fitzgerald SG, Cooper R, and Boninger ML address the question in their article, Impact of a push rim-activated power-assisted wheelchair on the metabolic demands, stroke frequency, and range of motion among subjects with tetraplegia. The study focuses on users with spinal cord injuries, but the results can be applied more generally. Here's a summary of what the article discussed:
Metabolic Demand: How Hard Does My Body Have to Work?
The first thing the researchers looked at was metabolic demand. They did this by examining heart rate and oxygen consumption. What they found was a significant reduction in both heart rate and oxygen consumption when the test subjects used the power assist wheelchair instead of the manual wheelchair.
This means that it takes less energy to use a power assist wheelchair, which translates into the ability to travel longer distances with less fatigue. If you're the type of person who has no problem when out and about for an hour or two but struggles to make it the whole day, this reduced metabolic demand may be just what you need.
Without completely eliminating benefits of physical activity like a full power wheelchair, a power assist wheelchair reduces the work requirements while enabling you to remain active.
Stroke Frequency: How Often Do I Have to Push?
The next variable the researchers looked at was stroke frequency. Here they measured how often the test subjects needed to push. Similar to metabolic demand, the study found a significant reduction in stroke frequency for power assist wheelchair use when compared with a manual wheelchair.
This result is important for everyday wheelchair users because of their heightened risk for injury due to repetitive motion. Wheelchair propulsion is difficult and ergonomically awkward. If you are a wheelchair user, you can adjust. But as the study states, “Many researchers agree that propelling with a high cadence … can lead to upper-extremity pain and cumulative trauma disorders.”
By limiting the number of pushes required, you can avoid the potential pain, injury, and loss of independence.
Range of Motion: How Awkward Is It to Propel Myself?
The final area examined by the researchers was the range of motion. While it's healthy to utilize your full range of motion if possible, it's not healthy to overextend. Overextension is typical with wheelchair use as there’s a tendency to stretch to get every last bit out of each push. The study found that range of motion was reduced for joints from the shoulders to the wrists when using a power assist wheelchair versus a manual wheelchair.
Reduced range of motion means your shoulders, wrists, and hands can operate in their normal range., which reduces the likelihood of a shoulder tear, carpal tunnel syndrome, and the other common injuries suffered by wheelchair users.
The study concludes, “For subjects with tetraplegia, [power assist wheelchairs] reduce the energy demands, stroke frequency, and overall joint ROM when compared with traditional manual wheelchair propulsion.”