A team of experts in biomechanics and physiology that conducted experiments on Oscar Pistorius, the South African bilateral amputee track athlete, have just released their findings in the “Journal of Applied Physiology.” Some of their previously confidential findings were presented to the Court of Arbitration for Sport (CAS) in Lausanne, Switzerland in May of 2008. Other findings are now being released for the first time.
A portion of the team’s findings had been presented at the CAS to appeal the eligibility ban that had been imposed on Pistorius by the International Association of Athletics Federations (IAAF) barring him from sanctioned competitions, including the Olympics and World Championships.
The IAAF had claimed that the Cheetah Flex-Foot prostheses (J-shaped, high-performance prostheses used for running) worn by Pistorius give him an advantage over able-bodied runners.
“I am pleased that we can now completely disclose our results as our study includes critical new data not presented in the CAS eligibility hearing,” said Peter Weyand, lead author of the study and an associate professor of applied physiology and biomechanics at SMU.
Photo: Weyand observes Pistorius on treadmill (Credit: Jeff Fitlow/Rice)
“In addition to informing an interested public, full disclosure is in the best interests of Oscar Pistorius, other athletes and the sport of Track and Field,” Weyand said. “The controversy raised by Oscar’s inspiring performances presents a pivotal case for the future regulation of prosthetic and other technology in organized athletics. Accordingly, disseminating all the available facts is essential, and I am relieved that all of our data are now available, particularly the mechanical data that are most relevant to the controversy and which were not part of the CAS hearing.”
The eligibility ban appeal was successfully presented on behalf of Pistorius by the international law firm of Dewey & LeBoeuf who took the case on a pro-bono basis.
The CAS concluded that the IAAF failed to prove that the biomechanical effects of the Cheetah prostheses give Pistorius an advantage over other athletes not using the prostheses.
The authors of the study are Weyand of Southern Methodist University; Matthew Bundle of the University of Wyoming; Craig McGowan of the University of Texas at Austin; Alena Grabowski and Hugh Herr of the Massachusetts Institute of Technology; Mary Beth Brown of Georgia Institute of Technology; and Rodger Kram of the University of Colorado at Boulder.
None received compensation for the research or work on behalf of the CAS hearing. The group agreed to conduct the experiments with the understanding that they would be able to publish their scientific findings after the CAS hearing.
The experiments were conducted at the Rice University Locomotion Laboratory in Houston.
The scientific team compared Oscar Pistorius to track athletes with intact limbs to evaluate their: energy cost of running; fatigue resistance; and sprinting mechanics.
The team concluded that:
- Pistorius’ energy cost of running is similar to that of accomplished male distance runners, but 17 percent lower than that of performance-matched male sprinters.
- Pistorius’ ability to hold his speed over longer sprint races is identical to that of intact-limb athletes.
- Pistorius’ sprinting mechanics are markedly dissimilar to intact-limb track athletes. At top speed:
- Pistorius exerts considerably less force on the ground in relation to his body weight than intact-limb runners.
- His foot is in contact with the ground 14 percent longer on each sprinting step.
- He spends 34 percent less time in the air between steps.
- He takes 21 percent less time to reposition (swing) his legs between steps.
In summary, the team concluded that Pistorius’ physiology — energy cost and fatigability — is generally similar to that of intact-limb athletes, but his sprint running mechanics are markedly dissimilar.
The group’s paper in the “Journal of Applied Phsyiology” concludes:
“The mechanical dissimilarities observed between Pistorius and intact-limb runners result from functional trade-offs that are perhaps inevitable for artificial vs. biological limbs. The aerial and swing time reductions observed for Pistorius may be due to his light-weight prostheses. However, the meager forces he exerts on the ground may be a critical limitation for speed. Legs must perform different functions during the stance and swing phases of the stride, as well as during the start, acceleration and relatively constant-speed phases of sprint running. Collectively, the results underscore the difficulty of providing these multiple mechanical functions with a single, relatively simple prosthetic design, and the formidable challenges involved in engineering limbs that fully mimic those produced by nature.”
The study results were posted June 18 to the online site of the “Journal of Applied Physiology.” Read the article.
Pistorius competes in the 100-meter and 400-meter sprints. The Cheetah legs have earned him the nickname “blade runner.” While his time was such that he just missed qualifying for the 2008 Beijing Olympics, Pistorius reportedly will try to compete in the London Olympics in 2012.
Weyand is an associate professor of applied physiology and biomechanics in SMU’s Department of Applied Physiology and Wellness in the Annette Caldwell Simmons School of Education and Human Development.
Related links:
Peter Weyand
JAP Study: The fastest runner on artificial legs: different limbs, similar function?
LA Times: Does Pistorius have competitive edge?
New York Times: An amputee advantage?
Times: Oscar Pistorius to make run at London 2012
Study revives Olympic prospects for amputee sprinter
T.O. Sports: Blade runner beats the ban and his ‘Cheetahs’ are no longer ‘cheating’
AFP: ‘Bladerunner’ Pistorius wins appeal against Olympic ban
IAAF: Pistorius is eligible for IAAF competition
New York Times: Amputee ineligible for Olympic events
TIME Magazine: How Fast Can Humans Go?
Science Daily: Oscar Pistorius, amputee sprinter runs differently
His years of research on creatures ranging from goats to antelopes to kangaroos indicate that smaller animals expend much more energy per pound to locomote. For example, a mouse expends 30 times more energy than an elephant in proportion to their weights, while human children use about twice as much energy as their parents to cover the same distance, he says.