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Among the toughest, most circular arguments in the mobility field regards footplates being too close to the ground for users' preference. And, such conversations go like this:

“I want to raise my wheelchair's footplate higher for more ground clearance,” says the consumer.

“The only way to accomplish that is to raise your entire seat-to-floor height since it's a fixed distance between your seat and footplate, based on your leg length,” replies the provider.

“But, I can't have a taller seat-to-floor height because then my knees won't fit under tables, and transfers will be hard,” says the consumer.

“Then you can't increase your footplate clearance,” says the provider.

“But, I want to,” replies the consumer.

“Then you're OK with a taller seat-to-floor height?” the provider asks.

“No,” says the consumer.

....And, the conversation goes on forever!

The fact is, on power and manual wheelchairs alike, among the few fixed distances is between the seat pan and footplate, based on one's knee-to-heel lower leg length. It's a formally fit dimension, optimizing positioning and pressure management – and it shouldn't be changed once set at the proper leg length.

As a result, footplate height ties directly to seat height. Raise the seat height, and the footplate raises. Lower the seat height, and the footplate lowers. And, in this way, if one wishes a low seat-to-floor height, and has average to longer legs, the footplate is often close to the ground.

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Based on the illustration, we see the direct correlation between seat-to-floor height and footplate clearance. In the example, a 16” leg length with an 18” seat-to-floor height equates to 2” of ground clearance under the footplate. In order to get 4” of ground clearance under the footplate – again, because one's leg length stays 16” – the entire seat must move upward, to a 20” seat-to-floor height.
(If one were only to move the footplate upwards, it would distort one's positioning.)

An alternative is to use a lesser legrest angle, where one's feet are positioned outward and forward. However, most users resist a 60-degree leg angle, for example, because it dramatically increases the overall length of the wheelchair (one's feet protrude far forward).

On power wheelchairs with power elevating foot platforms tucked close to a 90-degree angle when fully retracted, some users take issue with having to elevate the foot platform or slightly tilt the seat for outdoor clearance. However, again, footplate clearance directly relates to seat-to-floor height, and if one does have a low seat-to-floor height, footplate ground clearance may be compromised, requiring slightly elevating the foot platform or tilting the seat in some cases when venturing on uneven terrain.

Therefore, if you've ever wondered why you can't have both a low seat-to-floor height and maximum footplate clearance, now you know the answer: Your leg length sets the rule.

Published 6/2011, Copyright 2011, WheelchairJunkie.com