Page 20 - Mobility Management, January/February 2022

focus on ultralights By Laurie Watanabe What Camber Can Do for
Performance
Even sports fans with little under- standing of ultralightweight wheelchair setup will immedi-
ately notice that the rear wheels of chairs used for rugby, basketball or tennis look very different than the wheels on everyday manual wheelchairs.
They’re seeing camber, what United Spinal Association defines as “an angling that brings the top of the wheels closer to each other” (spinal- cord.org). With camber applied, a chair’s rear wheels are no longer perpendicular to the ground.
Camber can offer many functional benefits... but as with all wheelchair setup choices, adding camber
to a system is a matter of careful balance.
Less Energy & Effort Expended
Lauren Rosen, PT, MPT, MSMS, ATP/ SMS, is the Program Coordinator for the Motion Analysis Center at St. Joseph’s Children’s Hospital of Tampa, Fla.
“It’s the angle between the top
of the wheel and the bottom of the wheel,” Rosen said, in explaining camber. “Camber helps with stability, and it helps with turns. That’s why when you see the sports chairs — tennis, basketball, rugby — they all have a huge amount of camber in them. Because that makes you super stable, and that makes you turn on a dime. Those are two things you need for playing all of those sports, espe- cially basketball and rugby, where there’s chair-to-chair contact.”
But wheelchair stability is crucial to efficiency and function, even if your clients aren’t aiming to compete in the Paralympics.
“It makes the chair feel more stable laterally,” Rosen said. “It’s not
Significant camber is clearly visible in the sports chair used by Chuck Aoki, a three-time United States Paralympian in wheelchair rugby, seen here competing at the Tokyo Paralympic Games last year.
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going to stop fore/aft tipping; that’s about center of gravity and casters, etc. But camber makes the chair more stable laterally, so if I need to pick something up off the ground or reach to the side, it makes my chair more stable.”
Camber also makes turning
the wheelchair a more effortless endeavor. “It puts less of the tire in contact with the ground, so it turns easier,” Rosen said.
How Much Camber Is Ideal?
So if adding camber to a system makes the wheelchair easier to turn and also makes it laterally more stable, what’s the down side?
Well, splaying the rear wheels outward can make a wheelchair substantially wider. The more camber it has, the wider the chair gets.
Camber is measured in degrees, and Rosen pointed out, “[In sports chairs], it’s like 15° or 20°. It’s a significant amount. For a lot of those guys and girls, they have to take at least one if not both wheels off to get through a door.
“That’s why you see a lot of them bringing their day chair and their rugby chair, because that rugby chair won’t go everywhere. That’s why they don’t leave their day chair at home and just travel in the rugby chair, because it’s ridiculous to try to make it through doors in something with that much camber.”
Larger amounts of camber can interfere with accessibility. Smaller amounts of camber, though, can offer multiple benefits without causing doorway problems.
“The only reason I would ever give
CHUCK AOKI: SHUTTERSTOCK/MARCO CICCOLELLA