Gearing Up to Boost Comfort for Wheelchair Users

Posted on October 7, 2015

It takes more than 20 muscles in the arms and upper body to propel a manual wheelchair. That constant repetitive motion usually causes shoulder injury and pain for people who depend on wheelchairs for mobility.

Getting around hurts, but Vaishnavi Muqeet, a physician at the Clement J. Zablocki Veterans Affairs Medical Center in Milwaukee says, it doesn’t stop most of her patients from using a manual wheelchair. The reason, she says, is they fear that they will lose their main form of exercise – and their independence.

On the fast track to intervention is Brooke Slavens, assistant professor in UW-Milwaukee’s College of Health Sciences, Department of Occupational Science & Technology.

Assistant Professor Brooke Slavens prepares for motion capture and muscle activity assessment to investigate the biomechanics of manual wheelchair mobility with a geared wheel system.  She is placing a reflective marker on the wrist of a human subject, while he is seated in a manual wheelchair.

Assistant Professor Brooke Slavens prepares for motion capture and muscle activity assessment to investigate the biomechanics of manual wheelchair mobility with a geared wheel system. She is placing a reflective marker on the wrist of a human subject, while he is seated in a manual wheelchair.

Slavens has joined with an Illinois startup company, IntelliWheels, on a research project that proposes an entirely different idea for manual wheelchair assistance.

The company has created a multi-geared wheel system that operates much like the gears on a bike. This system allows the user to maintain a steady speed on an incline with the same amount of effort as on level ground.

“There are no solutions that are similar to what we are doing, so it’s a unique aspect of a simple concept,” says Slavens.

She and Muqeet are testing the IntelliWheels prototype with patients at the VA hospital who have spinal cord injuries. The research collaboration also includes the University of Illinois at Urbana-Champaign and TiLite, a manufacturer of ultra-light wheelchairs.

The project, funded by the National Institutes of Health (NIH), could be an ideal compromise for chair users: They can manage their discomfort while continuing to use a manual wheelchair.

“This study is giving us direct clinical interaction with patients,” says Slavens, “and it has great potential for changing how people use their chairs.”

Mapping joint stress

Adult manual wheelchair users make four distinct patterns with their arms and wrists to propel themselves. Slavens’ goal is to identify the most damaging aspects of those patterns.

With the help of some of the most advanced simulation software available, Slavens is revealing vital information that could help wheelchair users change arm-movement habits because they can actually see where the stress occurs by watching the animated program.

“We’re able to use our models to see when joint forces are really high with certain motions,” she says. “This is how we quantify which patterns result in the most force to the joint, and then we can provide recommendations to patients.”

Mentoring Slavens, as part of a prestigious Career Development Award from the NIH, are two experts in the rehabilitation field. One is Stanford University Professor Scott Delp. Slavens joins thousands of investigators in an international research collaboration using Delp’s OpenSim software to make and exchange biomechanical models.

Another mentor is Jules Dewald, chair of the Department of Physical Therapy and Human Movement Sciences at Northwestern University. Dewald’s work combines neurophysiology, imaging and signal analysis techniques, rehabilitation robotics and clinical testing.

“My ultimate goal is to help surgeons, clinicians and therapists improve someone’s life,” says Slavens. “And when that happens, there’s no limit to what people can do.”