This NASA Engineer Has Revolutionized The Wheelchair

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This topic is the second in a three-part series, presented by Rowheels, on the science of life in a wheelchair. Rowheels is reinventing the wheelchair with their patented reverse "pull" propulsion system, which curbs injuries associated with traditional "push" wheeling.

If you've ever spent time in a wheelchair, or know someone who has, then you probably know that simply trying to get around can be a cause of additional injury. In fact, up to 70% of individuals in traditional wheelchairs — that is, those that require a pushing motion to move forward — develop chronic shoulder pain. But Rowheels, a set of wheels that require users to pull in a rowing motion to propel the wheelchair forward, is hoping to end those repetitive-stress injuries once and for all.

There's Got To Be A Better Way

In 1998, when Salim Nasser was 20, he was hit by a drunk driver. Today, Nasser is a quadriplegic, and an engineer at NASA's Kennedy Space Center. Though Nasser himself is in a motorized chair, he knew about difficulties of life in a manual wheelchair from friends and physical therapists. Many, he says, experienced chronic shoulder pain, sometimes so bad that they had to move to a power chair. In 2004, when he was tasked with coming up with a senior design project for engineering school, Nasser envisioned the very first version of Rowheels: A wheel that uses a gear system to propel a chair forward as the user pulls back. In 2010, he entered the prototype into Tech Brief's Create The Future design contest — and won. Four years later, in late 2014, the first Rowheels were on the market.

The problem with standard wheelchairs, according to Nasser, is that they put strain on a limited number of weaker muscles, and can create muscle imbalances in users. And there are a lot of users — according to the CDC, 2.2 million people in the United States alone depend on wheelchairs from day to day. According to Rowheels, those weaker muscles "do all the propulsion work causing them to become overused and tight, destabilizing the shoulder joint." Many wheelchair pushers even develop Shoulder Impingement Syndrome, a condition that causes inflammation — and potentially even tearing — of rotator cuff tendons and surrounding tissue. Because using Rowheels relies on a pulling motion, it "distributes the propulsion work over a greater number of large muscles, resulting in less fatigue and overuse of individual muscles. Rowheeling muscles stabilize the shoulder joint and retract the scapula, improving posture and reducing the risk of Shoulder Impingement Syndrome," according to the company.

Salim Nasser, NASA engineer and Rowheels co-founder and CTO

The Wheel Of The Future

Aside from helping to avoid shoulder pain, Rowheels improve posture and strength, and, in the case of the REV-LX model, take about 25% less effort to propel forward. Jackie Justus, a spinal cord nursing educator at Zablocki Veterans Administration Medical Center in Milwaukee, told Popular Science that the chair's rowing motion could be a "big step forward and save [wheelchair users] a lot of wear and tear." Rowheels fit any chair, come in two models (the REV-LX is easier to use, the REV-HX is quicker) and are covered by insurance. All of which has us wondering, why did it take so long for someone to reinvent the wheel?

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Expert Insight

Salim Nasser
Co-Founder and CTO, Rowheels
How did the idea for Rowheels came about?

I was in a car accident about 20 years ago — I was hit by a driver under the influence — so I know the issues that people in chairs tend to have. Years later, I was in school for engineering and I had to come up with a senior design project, and I thought of friends who had hurt their shoulders pushing their chairs. I knew how un-ergonomic pushing a wheelchair is, so I thought of the idea of pulling. I ran it by a friend at the Miami Project to Cure Paralysis — I go to their gym a lot — and we talked about the muscles that pulling a chair would use. He validated my idea that a rowing motion would be a better way to go. So I worked on the prototype, but in the meantime I was a summer intern with NASA and was doing my internship at the Space Center in Houston. When I graduated, I ended up coming to work at the Kennedy Space Center in Florida and the Rowheels idea sat on a shelf for four years, until one day I received an e-mail at work calling for submissions to Tech Brief's Design the Future contest. I made a submission based on the Rowheels idea, not thinking I was going to win... and then I won the grand prize. In 2011, I heard from my now-partner Rimas Buinevicius, who had broken his leg in a yachting accident and was in a wheelchair for nine weeks. He had developed shoulder pain and was looking for a better chair option. And that's where Rowheels as a company began. I still work at NASA, but Rowheels is my passion.

Why is a product like Rowheels so important for wheelchair users?

Well, I'm a quadriplegic — my lower extremities are paralyzed, and my upper body is partially paralyzed — so I'm in a power chair. But people in manual chairs push, and when they push their chest muscles and the front muscles of their shoulders do all the work. Muscles in the front get stronger and tighter and shorter, and in the back the muscles get looser and weak. The shoulder joint gets out of balance, and you expose yourself to something called impingement. The same thing happens to body builders who focus on bench presses but neglect their upper back. Their shoulders get pulled out of whack and put in a position where you can pinch your rotator cuff. In a wheelchair, you push 2-3,000 times a day. That's about a million times a year that you could pinching and pinching your rotator cuff. People start developing pain and injury, and the pain can be so bad that they have to go to a power chair. When your activity is already limited because you're in a chair, moving to a power chair is a big deal. Your muscles atrophy because you're not as active. You can't reach a book on a high shelf, sure, because you're in a chair, but now you're also missing the cardiovascular work you can get on a regular basis.

Why do you think someone hasn't tried out this approach before?

If I wasn't in a chair I would never have thought of this. It's about perspective and understanding where people are coming from. I'm not in a manual chair, but I have been exposed to the issues. But of course, when I've told physical therapists or other engineers about it, they say "Why didn't I think of that?"

Are there any user success stories that really stick with you?

Scott Chesney, our spokesperson, has been in a chair for 30 years. When he first joined the company he had shoulder pain that was bad enough that he had a hard time sleeping and was on medication. Within a month of getting on Rowheels full time he was off the meds, and after three months his pain went from 7 on the pain scale to a 2.

What is your dream for the future of Rowheels?

My dream would be that before anybody even gets in a situation where they develop a shoulder injury, the first thing the physical therapist says is "let's put Rowheels on the chair to prevent future issues." That would be ideal — it would prevent future costs for surgery, or shots of cortisone. I hope that one day every person who comes out of the hospital and needs a chair has Rowheels.

Watch and Learn: Our Favorite Videos On The Science Of Wheelchairs

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Written by Curiosity Staff February 24, 2017
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