Doug Garven knows a lot about seat slope.
For one thing, his education and background are in industrial
design, and his body of work in creating highly functional, highly
attractive ultralightweight manual chair is well admired.
But he’s also a consumer who knows that the many dozens of
individual measurements and specifications for that ultralight chair
are more than just a list of numbers on an order form. They impact
such critical factors as propulsion efficiency and posture, and can
ultimately determine how comfortable, safe and functional the
We asked Garven, a member of TiLite’s industrial design team in
the manufacturer’s engineering group, about his personal experiences
with seat slope.
On finding the “right” seat slope: “Like everything with wheelchairs,
it’s a compromise. You do one thing, and it solves the
problem, but it creates another, and it’s always trying to find that
sweet spot that gives the best of both worlds. It’s different for
every single user because of what their abilities are, what their
injury level is, what their wheelchair skills are. All that plays into
On the seat slope he personally prefers today: “I sit at a 2" difference from front to rear. And that is kind of an industry standard.
If you take a sampling of chairs, most of them fall into that
range. That’s for your average para.”
When typical seat slopes vary: “I’ve sat in a deeper seat-dump
chair. Sports chairs will all have that because of the added stability
it creates. But there’s your trade-off again, too. If somebody’s at a
real low injury level, they can sit a lot taller and straighter, and it
gives them improved eyesight and better interaction with ablebodied
people, but you have the tradeoff of losing good propulsion
on your wheels if you sit too tall. Typically, it’s a rule of thumb
that when you drop your hands down by your side with your
fingers extended, you would like the fingertips to be at the center
of the wheel. That gives you the most range on your push stroke.
“In a sport application, you’d want to sit even lower and get that
extra stability, but for every day that doesn’t become practical for
the things that we were mentioning. It’s harder to transfer out of,
and it’s easy to get under tables, but you’re so low to the ground that
you lose the ability, I think, to communicate with people. You almost
make them feel obligated to kneel down when they talk to you.
“Ten to 15 years ago, when your everyday chair was your sports
chair, (seat slope) was an adjustment they would do a lot. But the
sport chairs have all evolved into their own specific chairs, as has
your everyday chair.”