Page 17 - Mobility Management, May 2019

Bart Van der Heyden, PT, Bodypoint’s Country Manager, noted that a lack of core stability can result in a long list of problems, including these:
• Fall risk, and the user working too hard to keep his/her trunk positioned against the back of the wheelchair, or going into posterior pelvic tilt and sliding in the chair.
• Shoulders moving forward, lack of head alignment, neck pain.
• Collapsing chest and difficulty in holding the upper body in place.
• Inability of the legs to stay together.
• Stiffness in calves or ankles; feet fall off of footplates.
• Fatiguing from the strain of reaching to the side to grasp
the joystick.
• Fatigue during activities that require greater range of
motion, such as playing sports or traveling, even if the user generally does not have a stability problem.
“If a wheelchair user is sliding and slouching in the chair,” said Matthew Kosh, Bodypoint’s President and co-founder, “then simple activities such as reaching or propelling the wheelchair are more difficult and tiring. Posterior pelvic tilt results in a kyphotic posture, which reduces upper-body strength and requires more effort to balance the weight of the head — natu- rally, it is a more exhausting way to sit. A kyphotic posture further results in shallow breathing, lowering blood oxygenation and stamina. Lastly, if seated with a posterior pelvic tilt too long, there is an increased risk for sacral sores, which ultimately has the most damaging effect on sitting tolerance.”
Stability for Manual & Power Wheelchair Users
A lack of core stability for a manual wheelchair user can make the act of self-propelling much more labor intensive.
“One of things often overlooked by self propellers is how much their position slips while propelling the wheelchair,” Simpson said. “Most self-propellers don’t even realize this is happening.”
Athletes, she noted, are typically more aware of their body positioning: “Wheelchair athletes recognize the need to secure the pelvis, and in many sports strap themselves into the chairs. These athletes want to feel like part of the chair rather than just sitting on top so that they can better control their chair and perform their sport.
“When working with these athletes, Bodypoint asks them to try a belt in their active chairs to test whether their push strength is greater and more efficient. The universal response is that securing their thighs/pelvis absolutely increases push strength and efficiency, which in the long run will protect their shoulders and provide more longevity in pushing their chair. Non-athletes can benefit from the same principle.”
For power chair users, a lack of core stability can be even more dire.
“Obviously, all the solutions mentioned previously can apply to the power chair user,” Simpson said. “One thing that is often overlooked, however, is the position of the joystick control. Imagine you were trying to write a note, but had to do it off to the side rather than putting the paper centered in front of your
body. Your penmanship might suffer. Yet the power chair user is expected to perform all the power functions of the chair with a joystick placed at the end of one arm of the chair.
“Many power chair users will sit better, with improved core strength and endurance, when a midline joystick is mounted on their chair. It is often more natural and easier for the power chair user to manage the power functions of the chair with the joystick mounted in front of their body rather than off to one side.”
Power chair users, Sayre said, can have a lot of trouble reposi- tioning themselves once they get out of their optimal position.
As part of the research process that went into designing a new power chair, Sayre interviewed current power chair users. She recalled what a client who had multiple sclerosis told her.
“She said, ‘It’s so hard because I fatigue, and when I’m going outdoors, and I hit a bump, I’m not in midline. I’m pushed over. And it’s harder for me to get up and back into midline. If I had a smoother-riding wheelchair....’ That’s why we work so hard on putting suspensions in our chairs. When users get knocked out [of midline], it changes their whole function. It changes their strength. They can fatigue a lot easier.”
Core Stability Strategies
Creating or supporting core stability isn’t just a matter of building up a seating system. It’s designing a system that’s going to work with the client without getting in the way of the client’s goals and activities.
“We’re designing seating systems, the cushions and the backs, to work with the person, not against the person,” Sayre said. “I feel it’s like an exoskeleton of the body. The seating system needs to do what the body can’t do for that person.”
For a manual wheelchair user, adjusting seat-to-floor height so the rear height is lower than the front height can help
with stability.
“We talk about putting dump in the chair because [users] have a poor core to begin with, so they collapse their trunk,” Sayre explained. “Some of those clients wear abdominal binders because it helps to maintain the core and helps them to propel that chair and not collapse. Some people will add dump and create more slope because now you’re closing that hip angle. If when you’re sitting you collapse your ribcage on your pelvis, you’re creating stability there. And you’re able to propel.”
Sayre believes in choosing a seat cushion and a backrest that will work together, as two parts of a unified system, rather than choosing those components separately.
“The seating system — the back and the cushion — need to function together,” she said. “You want to keep that pelvis nice and tight, so you’re going to build into that seating system a little bit more for that person to have functionality.
“People tend to think about the cushion all the time and forget about the back. But the back is just as important as the cushion. They really need to work together. That’s why it’s called a seating system.”
She explained that a seat cushion isn’t capable of performing all of the positioning functions that some clients need: “You can’t get everything out of the cushion. With the pelvis, you’re trying
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