On August 28, 2024, one month after the end of the Paris Olympics, the 2024 Summer Paralympics will begin. Until September 8, athletes from 91 nations will compete in 22 sports. In front of spectators and television viewers from around the world who will follow the competitions, the athletes will rely on an impressive range of prosthetics, wheelchairs and other high-tech assistive devices. These devices are not very similar to those we encounter in everyday life, and even more, they vary considerably from one sport to another. For example, more than half of the 22 sports require a wheelchair, and this will be specific depending on whether it is basketball, fencing, rugby, table tennis, etc. The idea is therefore to adapt to the athlete and their sport. So “we design the equipment to get the best possible performance based on the constraints and needs,” adds Bryce Dyer, from Bournemouth University in England, where he develops prosthetics for disabled athletes.
Blade runner by bike
Another example is blade-type prostheses – which are elastic in order to better store and release energy – which are well known in athletics since the exploits, and setbacks, of South African Oscar Pistorius, nicknamed “The Blade Runner”. But athletes with similar disabilities, i.e. lower limb amputees, competing in cycling events have different requirements, because their prostheses perform a different type of movement than that of a race and at much higher speeds.
“One of the main forces that slows you down when you exceed a certain speed is aerodynamic drag. And the greater the drag, the greater the effort required to mitigate and overcome it,” explains Bryce Dyer. The legs of able-bodied people “are not particularly aerodynamic; they have not been shaped by natural selection for this task. On the other hand, it may be a criterion for designing a cyclist’s prosthesis.” And in fact, the engineer created such devices with a flat central section, the thin edge of which is turned forward, unlike blade prostheses for running, where it is the wide side that is oriented in the direction of the trajectory. “We can make that flat portion very, very thin,” he continues, “almost like an airplane wing – with the thickness of a razor blade – to cut through the air.” [et] reduce or eliminate any turbulence.”
British athlete Richard Whitehead has a prosthetic leg without a ‘knee’ joint, which gives his running a distinctive style.
© B. Lenoir/Shutterstock
Like in an armchair
As we said, wheelchairs vary considerably depending on the sport they are used for. However, they do have some similarities. For example, many are made from high-tech materials, such as carbon fiber, which make them both strong and lightweight. Their wheels are often covered in rubber that athletes grip with gloved hands to maximize friction and control movement as best they can. But beyond that, designs vary. In fencing, for example, the wheels are locked while athletes attack and dodge from set positions. So the chairs are equipped with leg straps and sturdy handles to help the athlete stay seated. In addition, many have a lower back than usual to allow for more upper-body movement.
The basic shape of a fencing chair is very similar to that of a regular wheelchair. This is not at all the case with those designed for racing, and therefore for moving at high speeds. A third wheel at the front gives them a low and elongated shape, which adapts perfectly to the position of the athlete: kneeling and leaning forward. The spoked wheels are usually replaced by smooth discs that generate less turbulence, thus reducing the effort required to move.
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For sports that require greater maneuverability, another design element is needed. “The tires or wheels are tilted,” explains Becca Murray, a retired American wheelchair basketball player who competed in three Paralympic Games and won gold at two of them. “This allows you to be faster and turn faster and more abruptly than with a regular chair.” Additional wheels at the back of the chair also make these quick turns easier and add stability. But these chairs sometimes tip over, which is why a sturdy design is needed. This is also why athletes wear straps or belts at the hips and legs. “If you fall, you must be able to get back up,” explains the former sportswoman. “So you want your wheelchair to stay attached to you, as if you were one with it.”
Tailor-made
In addition to being tailored to a specific sport, a device must meet the unique needs of each athlete. “Most of the equipment is custom made and designed to get the most out of the athlete’s body,” “For example, some prosthetic legs for athletics include mechanical knee joints when the athlete has had an above-knee amputation,” explains Ian Brittain of Coventry University in England. “But,” says Bryce Dyer, “there are unique athletes with their own style, like British athlete Richard Whitehead.” A multiple medalist in the 100 and 200 metres, he underwent two amputations above the knee and developed his own running style, with stiff legs: with each stride, he brings his legs back in a circular motion, from the left side then the right side.
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Wheelchair athletes also use adaptations to their equipment. For example, increasing the height of the backrest and tilting the seat backwards, creating a kind of “depression”, can help compensate for a muscle deficit. “I get a little hollow in my chair because I don’t have all my abdominal muscles to help me keep my balance,” says Becca Murray. “Actually, my knees are higher than where I’m sitting, which gives a bit of a tilt.” Players with spinal injuries may have even less core strength than the basketball player and need a rocker, even in their everyday chair. Others, amputees or knee injuries, have maintained and developed great core strength and do not need such a “dip.”
From the stadium to the street
The technologies used by the Paralympics often increase speed and mobility in sports, but they are unlikely to be useful for equipment that non-athletes use in their daily lives. One reason is that the constraints are different, such as the need to keep the size as small as possible. “You want your everyday chair to be as small as possible, because you often have to move through tight spaces, such as through a doorway,” explains Becca Murray. “You need a vehicle that fits snugly around your hips and is as narrow as possible.” And it is clear that many public spaces are simply not designed to accommodate a wide range of wheelchair models.
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Thought-controlled prosthetics
Price is another consideration. “The market for elite athletes is incredibly small and in many cases these athletes are sponsored,” explique Bryce Dyer. “So some level of ‘trickle down’ is important, in the same way that technologies from Formula 1 eventually trickle down into everyday family cars. But sometimes it’s quite subtle.” For example, a barely visible component of a prosthesis, such as the socket that attaches the limb to the wearer’s body, can be improved.
Additionally, engineers and designers who work with Paralympic athletes learn techniques that are useful for other amputees. “A prosthetist can therefore take advantage of experience in sports to benefit individuals who are very active on a daily basis, those who want to jog, walk their dog, play tennis or other,” details Bryce Dyer. And adds: “It’s not just about appearance, it’s ultimately about expanding the range of possible activities.” Ultimately, many have to gain from the Paralympics, the athletes with the medals, but also society as a whole, this time in inclusion.
