Amputee runner may qualify for Olympics, but be denied chance to compete

This is a really difficult one.

I've been talking to a coach who works with a couple of athletes using Cheetahs. The "problem" is that the engineers and designers have done such a good job that the "feet" vastly outperform the human foot/ankle/calf muscle complex. They give some shock absorbtion, but have an outstanding rigidity, so that very little power is lost when the runner applies force. It's something that able-bodied athletes struggle to overcome.

And yet...how can one possibly argue that a runner with no lower limbs is running at an advantage? I don;t know what I think, but I do know I dont envy the IOC, who can't win, whatever they decide.

I've spent the last 8 years raising money for the Challenged Athletes Foundation; a charity that partners with OSSUR to provide athletes with the $30,000+ Flex-foot you see in the picture above. As Simon gets at in his post, the obstacles Oscar has had to overcome to get to the place he's at (in my mind) far outweigh the benefit he's receiving from the artificial limb. That said, the IOC has to draw the line someplace (we see it all the time with "equipment" - bike weight, too much neoprene in swimsuits, etc.).

For more info on the Cheetah, check it out here:
http://www.ossur.com/?pageid=3547#Cheetah

~BB

"if you run for yourself, you might let yourself down, but if you run for someone else, you'll never let them down..."

In running the human ankle complex returns over 250% of the energy absorbed at heel strike. The prosthetic foot complex is a passive system, and cannot return more enegry than what is put into it. You can think of it as a spring. No matter how good a spring you design, it cannot return more than 100% of the energy it absorbs. This comparison of course, assumes that the able-bodied and amputee runner will be putting the same amount of energy into the system. Since the only source of energy into the system is from the deceleration of the center of mass at ground contact. It is hard to see how an amputee (who also has a compromised energy absorbtion mechanism at the knee) will be able to put enough energy into the system to make up for what the elite athlete is able to apply. At some point we have to give credit where credit is due. The man is a well trained athlete and deserves to be treated as such.

250% plus energy return? I'm not sure I believe that. Figures for energy return vary widely according to the state of the athlete's body, the shoes he or she is wearing, and the surface being run on, so I'd like to know how this absolute figure was achieved.

What's perhaps more important, however, is that modern prosthetics are NOT passive, but dynamic. Energy return can be greater than that of a normal foot (ankle, calf, etc etc).

I asked the guys at Ossur about this and got interesting responses:

"This is a good question. I can not completely answer your question at this point but it is important to note that the FlexFoot, certainly considered a dynamic response foot, itself can not return more than 100% but it forms a foundation for the lower limb to push off from. So conceivably, the foot can tolerate far greater than 100% of push off generated by the patient biomechanically. I am not currenly aware of studies identifying just how much the Cheetah typically sustains for the average sprinter."
Duane Romo,CPO
Ossur Americas

"You are correct in your statement about energy return of the Cheetah. When comparing apples to apples (Cheetah to foot/anke/calf complex), the Cheetah will return around 95% of the force applied (there will always be some loss to heat), while the foot/ankle/calf has the ability to create energy in response to load (250%). Remember this isn't taking into consideration the contribution that the quads, hamstrings, and gluteal muscles will make, which will vary the total load outcome depending on thier relative strength, It might be conceivable that an amputee runner develops more strength in his/her quads, hamstrings, gluteal muscles from many years of compensation. The key here though, is that the foot/ankle/calf complex has a about a 2.5 to 1 energy return ratio when compared to the cheetah."

Brian Frasure
Ossur North America
Regional Clinical Manager

Looks like good ol' forrest gump is gonna make a movie about this young man's life:

http://www.timesonline.co.uk/tol/news/world/article1497140.ece

Blade Runner: Wired magazine has a great feature on Oscar in the March issue which is available online along with a video clip of the guy in action.

Author Josh McHugh has turned up another concern that might lead to the unthinkable being thought... that is that the runners who consistently losing out to Oscar at the moment... are single-leg amputees. He writes:

"Eventually, sports fans might be made to comprehend the distinction between bionics — mechanical joints with moving parts, microprocessors, and power sources — and what Pistorius runs on: pegs. Hyper-engineered, autoclave-forged, epoxy-impregnated, elastic pegs, but still really just pegs.

"But even that recognition might not be enough to quell concerns that Cheetahs confer an advantage. After he blew past them in Athens, Americans Shirley and Frasure accused Pistorius of “running tall”: adding length to his stride by using longer prosthetics. “He’s able to manipulate something that’s out of other athletes’ control,” Shirley told Sports Illustrated. “Just because he has a double amputation, why should he have a different set of rules?” '

Marlon Shirley ran 22.67 seconds in Athen, breaking Frasure’s world record for a one-legged amputee. But Pistorius beat them both in 21.97.

Later, McHugh concludes:

"The real asymmetry is that Frasure and Shirley each still have one natural leg, and it’s holding them back.You can see it when they run. Mixed-leg sprinters piston up and down, energy lost to vertical movement when they’re trying to go horizontal. When Pistorius runs, his gait has a circular smoothness. He looks like he’s on wheels. (Watch Pistorius run at wired.com /extras.) And while runners lose speed coming out of a turn as they straighten up, Louw thinks that Pistorius may actually be able to use that inward lean to push more energy into the Cheetahs. He’d come out of a turn going faster."

Great article and some fine pictures.

"Amputee athlete to compete in international able-bodied events. PRETORIA, South Africa -- International track officials changed their stance on champion amputee sprinter Oscar Pistorius and will allow him to compete against able-bodied runners while researchers try to determine whether his prosthetics give him an advantage.

But Nick Davies, spokesman for the International Association of Athletics Federations, said discussion of Pistorius competing in the Olympics was premature, noting the 20-year-old had not yet run times that would allow him to qualify."

New ESPN story online here.