August 2010- Certain sports require specific equipment. For instance, hockey players would not get very far without skates, and a bat-free baseball game defies logic.

Along those lines, athletes who use wheelchairs know they have to use a sport-specific model to attain optimal results on the track, court, field, etc. Invacare Top End, Pinellas Park, Fla., the sports and recreation rehab division of Invacare Corp., Elyria, Ohio, manufactures wheelchairs to fit this need.

In addition to everyday wheelchairs, the company designs and builds handcycles and wheelchairs for basketball, racing, rugby and tennis. "They're custom-built for the person and the sport they play," says Mary Carol Peterson, marketing and product manager at Invacare Top End. "You have a design that works better for" each sport.

Start to finish
Whenever Invacare Top End receives an order for a sports wheelchair, the first step is to take measurements of the person who will use it. Then the order specifications go to the company's on-site factory.

"We send out the order to have all the different tubing sizes cut and bent before it goes to the welder," says Peterson. "We transfer all of the measurements onto a shop form, and then the fabricator cuts the appropriate tubes that are set out. Every particular chair has specs so that tubes are cut to the right size and length so that it can then be all put together on a tray."

After that, welders take the wheelchair components and weld them together. For aluminum wheelchairs, the pre-fabrication and fabrication process takes about one hour, and welding takes three to four hours.

When manufacturing wraps up, Invacare Top End uses bead blasting to clean the wheelchairs, which are then painted with a powdercoat process.

"One welder can make two tennis chairs a day," says Peterson. "And our lead times are about four weeks right now."

Similarities and differences
Tennis wheelchairs share many characteristics with basketball wheelchairs. There are only two real differences, says Peterson.

One is that basketball wheelchairs have a wing that goes around the front to prevent potentially hazardous blocking during a game. The other is that unlike basketball wheelchairs, tennis wheelchairs have no major restriction for their anti-tip component.

Both these sports wheelchairs differ greatly from racing wheelchairs, which are not designed for courts, says Peterson.

"You can't really compare those at all," she says. "The racing chairs are designed to be stable and fast going up and down hills."

In regard to sports wheelchairs versus everyday wheelchairs, two major design differences distinguish the former from the latter.

"The camber, which is the slant in the wheels that allows for more stability, also allows you to turn very well, which is what you need when you're playing tennis or basketball," says Peterson. "But in everyday life, it creates too wide of a chair so that you can't get in and out of doorways.

"The other difference is that usually in the sports chairs you have your center of gravity set a little bit further forward so that you can turn better. You see in basketball and tennis that they move the axle position, or center of gravity, as far forward as possible so they can turn, but they have the anti-tipper there so they won't tip over backward. But in everyday life, the anti-tip would prevent you from going up a curb."

Past, present, future
Invacare Top End started in 1986, at which time it made all its sports wheelchairs out of chromoly. About five years later, the company started using aluminum for its racing wheelchairs.

In the early part of the decade, Invacare Top End switched to aluminum for its basketball and tennis wheelchairs.

Over the years, the company has relied on the same machinery to manufacture the wheelchairs, and other than going from chromoly to aluminum (and in some cases, titanium), the materials have remained the same. Some things are different, though, and have made a big impact.

"What has changed is the design and how you can make the design better so that people can perform better," says Peterson. FFJ

See the manufacturing process of the racing wheelchairs here.