Update 30 August 2011: Oscar Pistorius at the Daegu track in South Korea but he made history in competing with able-bodied athletes. He is still facing the same charges that his blades give him an advantage
On Friday, an international court ruled that amputee sprinter doesn鈥檛 get a boost from his carbon-fibre prosthetic legs 鈥� called Cheetahs.
After 2 days of testimony from a team of sports scientists who conducted extensive testing on Pistorius and his Cheetahs, the Court of Arbitration for Sport overturned a previous ruling that had kept the South African off the track.
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The decision means Pistorius can now compete against able-bodied runners and perhaps in the Beijing Olympics this summer.
麻豆传媒 takes a closer look at the science surrounding the decision.
Do the prosthetic legs give Pistorius an unfair advantage over able-bodied runners?
Probably not, says , a biomechanist at Rice University in Houston who led the testing. His team found that Pistorius burns just as much energy as other elite athletes. If the Cheetahs gave Pistorius an advantage, he would burn fewer calories while performing at the same level as other athletes.
To find out, Weyland鈥檚 team measured how much oxygen Pistorius consumed as he ran at a moderate pace on a laboratory treadmill.
They found that although he used oxygen more efficiently than many elite runners, he wasn鈥檛 off the charts, and many distance runners do better. 鈥淒oes he run cheaper than everyone else? The answer is no,鈥� Weyand says.
The (IAAF) also based their ban on the odd method of pacing Pistorius uses. Most 400-metre sprinters run the first half of the race faster than the second, while Pistorius is just the opposite 鈥� starting slow and gaining speed as the race goes on. 鈥淗e can run a good 100 metres, a better 200 metres, and an even better 400 metres,鈥� Weyand says.
The IAAF assumed that his pacing meant he got an advantage from the Cheetahs as the race progressed, but treadmill tests showed that eventually Pistorius too loses speed. His prosthetic legs actually slow his starts.
How did the IAAF get the science wrong?
The IAAF tested Pistorius and his prosthetics legs in the fall, but Weyand鈥檚 team says they over-interpreted the results.
One claim 鈥� that Pistorius runs 25% more efficiently than able-bodied runners 鈥� simply isn鈥檛 true, says , a researcher at the Massachusetts Institute of Technology in Cambridge, US, who presented Pistorius鈥檚 case.
That figure was based on an analysis of Pistorius sprinting on a treadmill at 9 metres per second. At that speed, a runner must produce some energy without oxygen, or anaerobically. The problem was that IAAF used a unreliable test to measure the anaeorobic energy that Pistorius burned while sprinting, says Herr.
Do his prosthetic legs return more energy than human legs?
There鈥檚 no way to know, says Weyland. The IAAF had claimed that the carbon-fibre Cheetahs returned six times more energy than a human ankle. 鈥淭he blade is a really simple mechanical device, but a biological one is a lot more complicated,鈥� he says. Dozens of muscles and tendons interact with every step, so it鈥檚 impossible to assess the mechanics at a single joint, says Weyland. 鈥淭here are too many unknowns.鈥�
What鈥檚 next?
For Pistorius, the ruling means that he can now race in sanctioned events against able-bodied runners. But it鈥檚 unclear whether he will race in the Beijing Olympics. 鈥淭he poor guy鈥檚 been fighting this for six months, instead of training,鈥� Weyland says.
Weyland and Herr鈥檚 team plans to publish their findings in a peer-reviewed journal. As the Cheetahs can be flexed and folded to gauge their mechanical properties in ways that human legs can鈥檛, 鈥渋t鈥檚 a great way for us to test our ideas about running鈥�, Weyland says.
Correction: The International Association of Athletics Federation is abbreviated to IAAF, not IAFF as originally stated in this article.
