New study further disputes notion that amputee runners gain advantage from protheses

Oscar Pistorius
Oscar Pistorius. Image credit: photograph by Elvar Pálsson, via Wikimedia Commons.

A study by six researchers, including a University of Colorado at Boulder associate professor and his former doctoral student, shows that amputees who use running-specific prosthetic legs have no performance advantage over counterparts who use their biological legs.

A debate on the matter was spurred when Oscar Pistorius, a bilateral amputee, was barred from the 400-meter dash at the 2008 Olympic Games in Beijing, and other able-body races. The International Association of Athletics Federations that barred Pistorius claimed his Cheetah Flex-Foot prostheses provided significant advantages over non-amputee competitors, agreeing with other studies that found prostheses reduce the energy cost of running. In addition, some have proposed that the lighter weight of specially designed sport prostheses facilitates a quicker swing of the leg.

The new study was published Nov. 4 in Biology Letters, a journal of the Royal Society in London, and is co-authored by Alena Grabowski and Hugh Herr of the Massachusetts Institute of Technology, Craig McGowan of the University of Texas at Austin, William McDermott of The Orthopedic Specialty Hospital in Murray, Utah, and Rodger Kram of CU-Boulder's department of integrative physiology and its Laboratory. Grabowski, lead author on the study, received her doctoral degree in integrative physiology at CU-Boulder under Kram in 2007.

After Pistorius was barred from the in January of last year, the U.S. research team presented findings in April 2008 to the Court of Arbitration for Sport in Lausanne, Switzerland, that were key in the reversal of the ban on Pistorius.

"We have already shown that Pistorius runs differently in terms of his biomechanics," said Kram. "Now we have much more clear evidence that his prosthetic legs incur significant disadvantages."

Data in the study include new measurements taken from an analysis of six unilateral amputees. The comparison of the amputees' prosthetic legs to their biological legs provided a more controlled test, according to Kram.

The researchers measured forces exerted on the ground and leg "swing times" while the unilateral amputees ran on a high-speed treadmill at The Orthopedic Specialty Hospital. The running-specific prostheses impaired the force production of runners by an average of 9 percent. Force production is generally believed to be the key factor behind running speed. No differences in leg swing times were measured.

One of Kram's undergraduate students, Matt Beale, also analyzed video from the 2008 Olympic and Paralympic Games.

"We found that Pistorius and the other amputee sprinters have leg swing times for both their prosthetic and biological legs that are very similar to those of Usain Bolt," said Kram. "We think the amputees learn that swinging their legs rapidly can help to partially compensate for their force disadvantage."

More information: The study can be viewed at

Source: University of Colorado at Boulder (news : web)

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Nov 04, 2009
It's possible, even likely that unilateral amputees don't fully take advantage of the unique characteristics of their prostheses due to difficulty in coordination.

Besides whether they give an advantage or disadvantage is besides the point what matters is that those prostheses are completely different then human legs and therefore those who use them should not compete against those who don't for the same reasons women don't compete with men - it's not a fair competition.

Nov 04, 2009
Ok, so let me get this straight. This fool lost both of his legs and his only desire is to compete in foot races. Granted, he has no feet but now that he's found a way to compete without an obvious disadvantage per the research and yet you still wish to deny him the same thing all us other humans want...nay, something we need? Competition.

So how is this any different than baseball players using steroids and still aloud to compete and perform and break records? I would consider that "not fair competition" but it still persists.

If it makes you happy I would suggest an asterisk next to his wins. Even though I do not agree with that either but not everyone can be satisfied.

Nov 05, 2009
I tihnk they should be allowed, and then when winning by miles, only then will it be obvious that there's an advantage. Let them in and see what happens, even if they aren't allowed a medal if they DO win, let them in anyway.
It's always a case of drawing a line somewhere with what gives an unfair advantage. People drink energy drinks when playing sport, should that be considered cheating? How about eating a banana? Something tennis players do a lot for the boost.

Nov 05, 2009
I say make a prosthetic only competition - then there would be no doubt that the winner wasn't at an advantage over the other participants. One thing i don't think the research accounts for is the energy expended during running, other runners have to flex all of the muscles in their legs while an amputee only flexes their upper thighs - if the prosthetic piece weighs less than a muscled runners leg then they can move it with less effort. I think that not tiring as quickly is clearly an uneven advantage over legged runners.

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