Game On
for Wheelchair Users


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Wheelchair basketball teams playing in the 2008 Summer Paralympics in Beijing. Image: Wikimedia Commons

Paul Schulte still remembers the first time he sat in a wheelchair physically designed for basketball. “It was a different kind of feeling,” he says. “I was amazed at how easily and how quickly that chair responded to me. I was excited by the things I could do with it.”

One of the things he ultimately did was play for Team USA in three different Paralympics, taking him everywhere from London to Beijing. It would also help take him to his present engineering career. As engineering manager for Top End, which designs chairs for sports from basketball to marathoning, he explained more about his company’s design for sports wheelchairs and the handcycle category.

Shingo Kunieda (JPN) at the 2011 U.S. Open Wheelchair Championship. Image: Wikimedia Commons

 

Anti-Tip Mechanism

For tennis wheelchairs, a large difference, he says, is in the amount of camber. “It uses 18-20 degrees camber in rear wheels and integrated into the design is an anti-tip[over] mechanism,” he says, “A main reason the rear wheels are in a forward position is to turn on a dime.” The most recognizable wheels are ones where the spokes are fiber rather than metal, he says. “The advantage in durability is clear when you’re talking about deforming issues with wear and tear.”

For basketball, the design involves two anti-tips, which brings more stability and helps the user to guard other players more closely, he says. “The frames these days are treated so we’re using 7005 aluminum alloy and then we’re doing our own heat treating of that material after welding,” says Schulte, who received his bachelor’s in mechanical engineering from the University of Texas at Arlington. “Where Velcro straps were used for securing an athlete into the chair in the past, now the same mechanism that’s used for skis and snowboarding is used to ratchet them into a basketball chair. They’re ratcheting padded straps.” For Schulte, he’s learned firsthand the physical level these chairs can get to. “It’s definitely contributed to a high level of play,” he says.

Brazilian athlete Wendel Silva Soares riding a Top End racing wheelchair. Image: Marcello Casal Jr / Wikimedia Commons

Handcycling Grows

A sport on the upswing, Schulte says, is competitive handcycling. He says the trend over the past 10 years has been for the bike to get lower to the ground and, for the handcyclist, it becomes even more aerodynamic. “For the handcycle, it’s also 7005 aluminum with heat treatment but you have carbon fiber wheels and high-grade components. The application is different because typically, leg power is a lot more powerful than arm power. With handcycles, we try to choose our gearing so the average user at a slow pace can climb a hill as opposed to an upright cyclist who can stand up on the pedals and generate that power. Handcycles involve a very reclined, aerodynamic position.”

Looking forward, Schulte believes a key goal should be to keep helping these sports creations become a better fit for athletes. “This is that story of the person who shows you that they can do much more than you thought,” he says. “You underestimate what these athletes can do and they’ll surprise you.”

Eric Butterman is an independent writer.

This is that story of the person who shows you that they can do much more than you thought.

Paul Schulte, engineering manager, Top End

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June 2015

by Eric Butterman, ASME.org