Last week, Oscar Pistorius, a South African Paralympics runner, was granted the chance to fulfill his lifelong dream of competing in the Olympics by the Court of Arbitration for Sports (CAS), in Lausanne, Switzerland. The court upheld the appeal filed by Pistorius against the decision made on January 14 by the International Association of Athletics Federations (IAAF) that banned the “blade runner” from competing against able-bodied athletes. The CAS ruled that the IAAF did not provide “sufficient evidence of any metabolic advantage … [or sufficient evidence] that the biomechanical effects of using this particular prosthetic device gives Oscar Pistorius an advantage over other athletes not using the device.”
Pistorius is a double amputee who competes on J-shaped, carbon-fiber, Cheetah Flex-Foot prosthetics made by the Icelandic company Össur. After Pistorius performed well in an international able-bodied event in 2007, suspicion arose among members of the IAAF that his Cheetah prosthetics may give him an unfair advantage. Immediately, the institution placed a ban on using “technical devices,” such as wheels and springs, in competition, and it decided to individually review Pistorius’s case.
The IAAF conducted a two-day scientific study, led by German professor Gert-Peter Brüggemann, of the prostheses. Based on the resulting data, the IAAF concluded that Pistorius indeed has an unfair advantage over able-bodied athletes, claiming that he uses 25 percent less energy than they do to compete.
Astounded by such allegations, Pistorius’s lawyers turned to MIT professor Hugh Herr and asked that he assess the scientific validity of the IAAF’s study. Herr, the director of the Biomechatronics Group in the MIT Media Lab, and also an associate professor in the MIT-Harvard Division of Health Sciences and Technology, assembled a team that included experts in biomechanics and physiology from six universities to evaluate the scientific evidence.
Technology Review sat down with Herr and asked him to explain the scientific flaws that the team of researchers found in the IAAF study, as well as the broader implications of the CAS’s ruling.
Technology Review: What were the claims made by the IAAF in its scientific report that you were tasked with assessing?
Hugh Herr: The first claim made by the IAAF was related to the metabolic energy required of Oscar to run. They claimed that Oscar, because of his Cheetah prostheses, was able to run at sprinting speeds with 25 percent less energy. In the second claim, the IAAF said the Cheetah prostheses release a greater amount of energy than the human ankle-foot complex in sprint speeds, and that that, in fact, introduces an artificial advantage to Oscar.
TR: In regards to the first claim, how did the IAAF come to that conclusion, and what scientific evidence did you use to refute that claim?
HH: At sprinting speeds, the body uses two sources of energy: aerobic and anaerobic. The problem is that you can measure one energy source but not the other. Anaerobic energy cannot be quantified by anyone–not here in the U.S., not in Germany; it simply can’t be precisely quantified. The IAAF claimed that it could be quantified, and they put a precise number on it: 25 percent energetic advantage at 400-meter-race speeds. This is deeply flawed because it can’t be quantified at those speeds. No one can assess quantitatively whether there is an advantage or disadvantage.