Published 4/03, Copyright 2003, WheelchairJunkie.com
Seating Solutions: |
A Strategy Toward Reducing Shock and Vibration
by Mark E. Smith
If Dorothy in the Wizard of Oz used a wheelchair, her experience traveling down the Yellow Brick Road
would be much different: Not only would Dorothy have to face the Wicked Witch of the West, but she also
might experience fatigue and pain due to the constant clickity-clack, bumpity-bump of her wheelchair
rolling over the bricks. |
Indeed, vibration and jarring can be a problem for wheelchair users,
no matter if it's due to the Yellow Brick Road or the sidewalk in front of the mall, increasing fatigue
and discomfort. The most obvious way to decrease vibration and jarring to your body is via suspension,
widely available on manual and powerchairs alike. However, much like the way bumps are still felt in
a luxury car, wheelchair suspension does not entirely eliminate shock and vibration transmissions to
the user. Further, suspension most often requires purchasing a new wheelchair, a difficult feat for
most whom have funding constraints. Fortunately, you don't have to suffer at the mercy of a rough ride
or spend thousands on a new chair - the proper selection of seating components can play as meaningful
of role as the best suspension systems, and with the added benefits of being applicable to almost any
chair, at a more practical price.
As wheelchair users, most of us recognize that a quality seat
cushion is the protective layer between our rear and the seat, reducing the chance of pressure sores.
However, a quality cushion is also a protective layer between your spine, hips, rear, and the ground,
isolating shock and vibration, doing a terrific job of absorbing impacts so your body experiences less
stress. Additionally, I've encountered many users over the years who have no history of pressure sores,
so they don't feel the need to sit on a high-end cushion. Yet, many of these users experience back problems,
exacerbated by shock and vibration when wheeling. As a rule, the same seating technologies that protect
your rear also protect your spine. Advance cushions of gel and air bladders do a fantastic job of insolating
vibration and absorbing shock, dramatically reducing those elements that increase fatigue and pain in
users. Furthermore, proper posture helps your body more naturally absorb shock and vibration, so positioning
characteristics of a cushion are equally important toward reducing fatigue and pain relating to impacts.
Therefore, when considering seat cushions, remember that they both protect your rear and your spine.
Your back doesn't, however, just benefit from the horizontal protective layer of a seat cushion;
it also benefits from the vertical and lateral support of a high-quality, cushioned backrest. Wheelchair
dynamics dictate that among the most common shock originates at the front of the chair - as with hitting
a curb-cut lip - sending shock waves multiple directions, including rearward (this is the "whiplash"
effect you my strive to avoid by dramatically slowing when encountering obstacles). The upper body may
be thrust forward on impact, then returning rearward into the backrest with considerable force. Additionally,
when one wheel or side of the chair experiences a shock, it may thrust the upper body side-to-side, stressing
the spine and surrounding muscles. For these reasons, a well-padded, contoured, rigid-shell backrest
with appropriate lumbar and lateral support can dramatically reduce back pain and fatigue. If you're
currently using sling-upholstery and experiencing back pain, exacerbated by your chair's rough ride,
consider moving to a contoured, rigid backrest for enhanced support and shock absorption.
Dorothy, the next time you find yourself traveling down the Yellow Brick Road, and your body feels every
crack, there's no need to wish for a better back, as the Tin Man wished for a heart - merely consider
upgrading your seating components for improved comfort.