The Olympic achievements of South African sprinter Oscar Pistorius have rekindled an old debate on whether the double amputee gains an advantage by competing on carbon-fiber limbs.
It’s an argument that’s nearly five years old, and Matt Bundle, an associate professor specializing in biomechanics and physiology at the University of Montana, still finds himself at the center of the debate.
“When there’s a big athletic meet that occurs, media interest in Pistorius ramps up,” Bundle said. “The issue turns to weather or not it’s advantageous for him to run on his lightweight, carbon-fiber prosthetics.”
This time, that big athletic event is the ongoing London Olympics, where Pistorius rose to international fame by qualifying in the semifinals for the 100-meter dash. While he failed to advance past the second round, he told the world he’d completed a lifelong goal by competing against the world’s top sprinters – the first double amputee to do so in Olympic competition.
But while Pistorius prepared to run, Sports Illustrated published a lengthy magazine article on whether the South African sprinter held a competitive advantage by running on carbon-fiber limbs against athletes with biological limbs.
The magazine analyzed evidence forwarded by Bundle and Peter Weyand, an associate professor of applied physiology and biomechanics at Southern Methodist University. Both Bundle and Weyand have argued for years that Pistorius holds a slight edge running on artificial limbs, and Sports Illustrated agreed.
“Sports Illustrated addressed one of the most contentious issues within their own analysis,” Bundle said. “What they found backs up what I and my colleague have been saying for years. Their results support our conclusion.”
Partially vindicated by the Sports Illustrated report, Bundle has been busy these past few days answering calls from the international media — questions about Pistorius and the biomechanics behind his speed.
Reuters, Discovery News, Wired, New Zealand radio and even a Chinese newspaper have called.
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“The most important thing the prosthesis do, and the advantage they confer, is how they allow Pistorius to swing his legs more rapidly,” Bundle said. “He’s missing half the weight of the leg, and more importantly, the distal half.”
Bundle and Weyand studied Pistorius at a lab at Rice University in 2008. Because the limbs worn by Pistorius weigh half as much as an intact lower limb, their research found, the runner is not bound by the swing times that apply to runners with biological legs.
Pistorius can reposition his lightweight limbs in 0.28 seconds, or 20 percent faster than most athletes, Bundle said. That faster repositioning time allows him to spend less time in the air between steps. Bundle said that reduces how hard Pistorius strikes the ground while transitioning into the next step.
“World-class sprinters will typically apply peak ground forces that are five times their body weight and do so during foot-ground contact periods that last less than one-tenth of a second,” Bundle said. “Slow runners are limited to lesser forces and longer periods of foot-ground contact simply because they lack the athleticism to do otherwise.”
Bundle said several facts surrounding Pistorius and his years-long struggle to compete against athletes with limbs have been misunderstood. Bundle’s own involvement, at times, has been inaccurately reported.
Among the falsehoods, Bundle said, was a 2008 ruling by the Court of Arbitration for Sport. Unlike some reports, the court never said that Pistorius had no advantage over runners on his carbon-fiber blades.
Instead, Bundle said, the court simply overturned an eligibility ban imposed by the International Association of Athletics Federations. He said the IAAF, in an effort to ban Pistorius from sanctioned competition, had failed to offer scientific evidence supporting the reasons behind its ban.
Four years later, the misconceptions and the debate have resurfaced, thanks in part to Pistorius’ dazzling Olympic performance.
“It’s a captivating story,” Bundle said. “His success is inspirational. But as scientists, our role is to provide sound, data-based conclusions on the basis of our scholarly expertise and nothing more.”