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Form & Function

Reprinted from SNS May 2017

Adaptive athletes demand a lot from their wheelchairs, and manufacturers are using lighter and stronger materials to meet those needs

For anyone who plays a wheelchair sport, a specialized wheelchair plays a major role in the game. Athletes spend a great deal of time learning how to maneuver their chairs to gain an advantage over their opponents.

But have you ever thought about the work that went into making that wheelchair? As adaptive sports continue to gain recognition and more programs start up around the country, the manufacturers of sports wheelchairs also continue to grow and evolve to keep up with athletes’ demands. 

With strong, lightweight materials tailored to an individual athlete’s needs, the sports wheelchairs made today are built to complement every style of play and ability level. 

How They’re Made

The first step in the athlete’s process is to get evaluated and measured, including his or her height, weight, leg length and hip width. From there, the sky’s the limit with countless customizable options that best suit the athlete’s comfort, range of motion, style and pocketbook. With such a wide variety of companies to choose from, athletes should schedule a talk and fitting with an expert in the field, their coach or a representative from their chosen wheelchair manufacturer about their specific needs and desires.

At Invacare Top End, for instance, once a shop order has been placed for a racing wheelchair, it goes out to the fabrication department. The fabrication department constructs all of the tubes used in building the racer. The tubes are delivered to a welder, who welds the main frame and cage, including the fender, head tube and camber tube. Then, it goes into the sheet metal area to be fitted with a kneeling pan if one is required, and sideguards, and then it’s sent through the paint process. It’s then taken to upholstery, where it receives the back and seat upholstery, as well as any strapping that’s necessary for that chair. Finally, it’s taken to assembly, where the fork, front wheel, rear wheels, steering component and track compensator are all assembled onto the chair. 

Paul Schulte, a senior engineer at Invacare Top End, says the average time to build a chair is seven to 10 days, but the timetable depends on the workload at the shop, as each chair is made to order and assembled by hand, one at a time. The maximum time is four to five weeks.

The process is similar at Per4Max, where athletes go through a 20- to 30-minute evaluation to find the best setup for their classification and position on the basketball court. 

Per4Max basketball wheelchairs start out as lengths of round tubing on a materials rack. 

“We cut everything to length, we bend it, we notch it and we jig everything up in our jigs that are adaptable to whatever the measurements for the end user are,” says Chris Kommer, Per4Max chief financial officer. “So there’s no two chairs for us that are the same. We tailor that chair to specifically what they need. When it comes to colors, when it comes to different adaptations for different athletes, whether their disability is an amputee or paraplegic or CP [cerebral palsy], we can make a setup that’s going to complement whatever their limitations are so they
can compete at their absolute highest level.”

Kommer says there are three levels of quality control to ensure the dimensions and the toe-in/toe-out are right before the chair is ready for paint.

“We go through a heat-treating process so everything is solidified, no potential for frame failures,” Kommer says. “And we provide factory support for these athletes, specifically at the international level and professional level. Just like any other professional athlete, they require factory support, whether it’s from Nike for their sneakers or whether it’s in motorsports, there’s factory support provided by, say, Honda, Yahama, Suzuki, when it comes to parts, components, adjustments, things these athletes require.”

Because of a backlog of orders, time to delivery is 10-12 weeks, but the actual production process takes about two and a half weeks, Kommer says. Both companies utilize 6000 series and 7000 series aluminum, which is strong, durable and cost-effective. The 7000 series is also about 20% lighter.

Schulte says the elite products in the Top End line use heat-treated 7000 series, and many of their chairs have carbon fiber or composite components in targeted areas, like the backrest and chain guard on the Force RX handcycle. 

“As long as Top End’s been around, we’ve been looking into different or new materials that we can utilize,” Schulte says. “Top End will always be hunting for another type of material, another application where we can utilize modern-age techniques and materials to deliver a better product. Top End has always had a strong tradition with the Paralympics. One of the other things that fuels the ideas is the Paralympics itself, so looking at how do we go faster, how do we help make the athlete even more agile, how do we help compensate for that person’s disability?”

Likewise, Per4Max looks for ways to lighten their chairs using carbon fiber in places where components would normally be aluminum-plated or plastic.

“We’re doing everything from wheels to different tires that hold more air pressure [140-150 pounds per square inch], to lighter components. How about titanium hardware? Everything we can do to shave ounces off while still maintaining that integrity and strength, as well as having a progressive setup that’s going to allow these athletes to go out and do what they weren’t doing before in their old chair,” Kommer says.

There are many types and sizes of wheels, including those with pushrims for racing chairs, handrims for basketball chairs and drive wheels for handcycles that all get added in assembly. 

Each company offers standard wheels and tires that are meant to be durable and get the athlete going. Upgraded wheels can be lighter and more aerodynamic, like a carbon fiber disc wheel or carbon fiber spoke wheel for racing, or stronger and able to take impact for basketball or rugby. 

Spinergy wheels and casters are popular upgrades for basketball chairs but can add $695 to $1,295 onto the cost of the chair. Wheel size and camber are generally specified by the athlete and depend mostly on the athlete’s size, strength and ability level.

In wheelchair racing, Schulte says, a 700c size wheel is used a majority of the time, while 26-inch wheels can be used by young athletes and those with shorter arms. In wheelchair basketball, there are four wheel sizes — 24, 25, 26 and 700c. If athletes want to sit tall, they have a larger wheel so they don’t have to reach too far. 

Per4Max has many different options of upholstery, from air mesh and solid cushions to pressure-relieving cushions, as well as tension-relieving backrest options. Top End provides standard cushions, no gel or memory foam, but there are other cushions available within Invacare, such as the Matrx line. 

“It’s not uncommon for an athlete to get an after-market cushion from a third-party distributor,” Schulte says. “Our recommendation to athletes is any issues with skin can be an athlete’s worst nightmare, so ultimately, athletes should take care when choosing their cushion. Speak with a health care professional. Sometimes people are surprised at how much of a different position you can get simply by adjusting the upholstery correctly.”

Making Improvements

When it comes to creating a new model of sports chair or improvements to an existing chair model, both Schulte and Kommer say the ideas for prototypes largely come from athletes’ requests.

“I know when it comes to my handcycle or any of the sport products I use, we’ve all got ideas about how something could go even a bit faster or be a bit better. Top End has talented fabricators who, at times, propose certain ideas. Our sponsored athletes are a great source of ideas and inspiration for us,” Schulte says. “It goes from a concept of, ‘Wouldn’t it be great if we had such and such?’ Then, we make contact with programs, athletes that we’ve targeted to work with and get their feedback, and if they’re saying, ‘Yeah, this is really needed, something like this,’ we’ll produce some prototypes and get some feedback.”

To that end, Top End recently released a product called the Preliminator, which is aimed at beginner level wheelchair racers. Schulte says the design team was reviewing the history of wheelchair racing and looking through older images of racing chairs. At the same time, they were becoming more aware of emerging adaptive programs in high school athletics.

“You look at the old wheelchair racers and they jumped into a chair. They certainly had their own way that they liked to sit and be set up, and then they were racing,” Schulte says. “And the racing chairs of today have evolved. But for some people it can be intimidating to measure themselves, get the measurements right, and so with the Prelim — we call it Prelim for short, meaning it’s a stepping stone and something preceding something greater ­— and so the Prelim is targeted at that first-time user experience. We get lots of requests for someone who wants to compete in a local 5K or wants to do the Marine Corps Marathon, so the Prelim was developed as a product that would be adjustable and help someone have a very positive experience with wheelchair racing very quickly and without necessarily being located close to someone who’s an expert or an athlete who can help them.”

Top End stocks five sizes of seat widths for the Preliminator: 10, 12, 14, 16 and 18, and there is also a custom version. The chair includes removable anti-tip wheels.

“For the best pushing location, you want a chair that’s fairly tippy so you’re able to make contact with as much of the pushrim as possible,” Schulte says. “Without the anti-tip, I’ve seen it fairly often trying to introduce new, young racers to the sport and someone has to walk behind them, holding the chair to make sure they don’t flip over. The idea the anti-tip serves is sort of like training wheels.”

In addition to full-welded, rigid-frame basketball chairs for higher tier athletes, Per4Max also makes a basketball chair designed for beginners and adaptive sports programs called the Thunder Adjustable model. The backrest and rear seat height are adjustable, as is the chair width to some extent.

“As athletes improve their core strength, balance and shooting skills, we want to keep improving the chair they’re using to provide a tighter fit, a more contoured fit,” Kommer says. “We’re constantly pushing the envelope. We’re constantly exploring different materials, different setups. The setup is huge, too. We’re evolving the chair setups to allow athletes to progress their game and evolve their game to even higher levels.”

Industry Changes

Schulte and Kommer agree much has changed in the sports chair industry in the past two decades. 

“From 1997–2007, court chairs have integrated anti-tips, click straps, and Spinergy wheels became more mainstream,” Schulte says. “In the last 10 years, the use of 7000-series aluminum has been more prevalent, some custom seating has been more prevalent in court chairs. When it comes to the racing wheelchairs, we’ve started to see more composites being used. We saw a big leap forward for wheelchair racing in the efforts of BMW. BMW did a full carbon [fiber] racing chair, and while other companies had done it before, they unveiled it in grandiose fashion. So, over the past few years, we’ve seen more use of composite materials, so that’s pretty exciting, where 10 years ago there were people tinkering with it, but it wasn’t becoming more mainstream like it is now.”

Top End is one of the first companies to choose a cookie-cutter design for a complete product. 

“We’ve been trying to have products produced that are ready to ship in less than five days, so we’ve chosen some designs that are produced, already in the box and ready for purchase,” Schulte says. “That’s something that’s changed in the last 10 years.”

Growth and development in handcycle construction was rapid, Schulte says. 

“From 2007 to now, it’s still an emerging marketplace,” Schulte says. “Where we used to have only a few handcycles, now we have lots of different handcycles for different needs, from the upright recreational rider, as well as a bike that’s completely recumbent, laying down, as fast as it can possibly be for the competitive racing Paralympic handcyclist.”

Kommer, who’s played wheelchair basketball for 20 years, says while basketball chairs are becoming lighter and have increased the camber and the center of gravity to allow the chair to be manipulated without input of the athlete’s hands, the biggest change he’s seen has been in the athletes themselves.

“When I first started, there was no anti-tip wheel in the back. Then, we evolved into having some more camber, and now commonly you’ll see two wheels in the back,” Kommer says. “What that allows us to do is have more of an aggressive setup. It’s just about positioning of your body over that wheelchair frame. We don’t want you to be on the chair, we want you to be in the chair, and we want that chair to react to every movement of your body. A lot of times at the high levels, you may push the chair one time and then you have to do a drill where you’re using your body to propel the chair from there. A lot of it, too, is the athletes and their willingness to put time in that chair, because chair skills, just the wheelchair doesn’t make the athlete. It’s a whole package.”

Purchasing a sports wheelchair is a big commitment, as they can range from around $2,000 to $8,000, so Kommer says it’s important to do your homework.

“One thing that’s the hardest part of adaptive sport is when you first get into that wheelchair, if you’re fighting the chair, it’s going to give you a bad taste for that adaptive sport, so the first wheelchair is crucial in determining the success of an adaptive sport,” Kommer says. “Educate yourself about wheelchairs, find a company that will work with you and help give you insight on exactly what you need. I think the biggest rule of thumb is never allow someone not in a wheelchair to tell you what you need in your wheelchair.”


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