Study of Specialized Weights Aims to Make Manual Wheelchair Users Stronger Faster

This story originally appeared in the spring/summer 2017 issue of FACETS, the magazine of the School of Health and Rehabilitation Sciences.

Picture yourself in the gym holding a dumbbell doing biceps curls. You know what happens, right? Over time, you build strength in that muscle.

Now imagine you’re using a dumbbell that has a high-frequency vibrator embedded in it. You’re not only working your biceps, but also your triceps, your deltoids and other muscles in your upper body. Your arm muscles will get stronger, faster.

That’s the hypothesis of Associate Professor Alicia Koontz and Assistant Professor Theresa Crytzer in the Department of Rehabilitation Science and Technology and their pilot study, which they hope will define new training guidelines for building muscle strength for people with paraplegia.

“Manual wheelchair users rely on their arms for just about everything,” said Koontz, principal investigator of the study. “The constant strain negatively impacts upper extremity health and frequently leads to other injuries such as shoulder pain.”

In the study, 24 individuals with spinal cord injuries who use manual wheelchairs have been randomized into two groups. Currently, each group is participating in a 12-week supervised dumbbell resistance and strength training program and a three-month follow-up assessment.

The vibration group holds a high-frequency (40 hertz) vibrating dumbbell in a static arm posture, and the control group moves a non-vibrating dumbbell through a full range of motion exercise.

“The vibration exerts force on the body and contracts the muscles,” explained Crytzer. “It’s extremely challenging because there’s a contraction every 40th of a second.”

The researchers believe this form of vibration training could benefit people with paraplegia who need to build upper limb muscle capacity and could possibly protect the joints from overuse and aging effects.

Koontz predicts there will be additional benefits as well: “We’re looking at how vibration training will impact both wheelchair propulsion and transfer ability. Will the wheelchair user be able to cross the street faster, for example? And will these individuals transfer higher or lower than they could before the training?”

Vibration training may also improve the general quality of life for manual wheelchair users. “With less pain, they may be able to reduce the number or amount of medications they need on a daily basis,” added Koontz.

According to Crytzer, who is part of an integrated team of rehabilitation specialists at the Center for Assistive Technology, this is a practical study with interdisciplinary implications.

“We always get requests for exercises for people with spinal cord injuries,” said Crytzer. “Down the road, we envision ways that vibration training could be incorporated into a course of physical therapy. It might even be delivered through a home health provider, improving accessibility as well as muscle strength.”