View Full Version : Re: amputee sprinter

05-17-2007, 04:39 AM
As much as I would like to see Oscar Pistorius compete with able-bodied
athletes, the Olympics is not the appropriate venue.

Someone commented that we should not make a ruling based on how big the
advantage is. I think this is a critical point. A ruling by the olympic
committe will set a precedent for all future athletes running with
assistive or replacement devices of any kind. Sure, today's versions
may not be truly optimized for a specific body stature at top sprinting
speed, but you can be sure further improvements will be made. Should a
BK amputee equiped with an energy storing prosthesis be allowed to high
jump? This doesn't sound fair to me. There already exists an event
where using an energy storing device is allowed, and in fact encouraged;
it's called the pole vault. Strapping an energy storing device to your
foot, or in a more unfortunate case to your residual limb, although
increadibly inspiring, seems no different than using a pole in pole
vault but with smaller gains.

Implications here reach far beyond sprinting. What about triple-jump?
Now there's an event where quick energy storage and release is at a

I think we do have the ability to do some "simple" calculations on
running speed limits, ignoring dynamics of the start. But is this even
necessary? We are approaching a continuum of allowance that could change
the future of the olympics and olympic records forever. I could see
potential to place ranges limits on mass, stiffness, and damping for the
case of sprinting, but I don't see such potential in jumping sports.

It may be the case also for running events, but at least in jumps, there
is an element of uncertainty at each hard plant and take-off regarding
whether the muscles will withstand the explosive forces on that
attempt. Some missed attempts and faults occur because the strength or
explosiveness just wasn't there when you needed it, or the muscle just
"gave out". These aren't issues you have with a prosthesis, lack of
explosiveness maybe, but is that enough to consider it "a wash"? As
Andy Ruina suggested, seperate classed could be designated for
carbon-foot athletes and skin-and-bone athletes. Until property limits
are designated, this is the only way to compete.

There is something to be said for the purity of the sport at the Olympic
level, and it should not be compromised for the sake of inspiration.

That being said, I hope that someone can prove convincingly by 2008 that
specific limits on his prosthesis will gaurantee there is no
non-anthropomorphic advantage, so that Oscar Pistorius might realize his
dream legitimately.

Joel C. Perry
Biorobotics Laboratory
University of Washington
Seattle, Washington, USA

Andy Ruina wrote:

> Ton and biomech-L: May 17, 2007
> About Oscar Pistorius and his carbon fiber feet. Do
> they give him an unfair advantage?
> Wouldn't it be great if there were a scientific answer to
> this question?! :) But for now, as best I know, no-one has
> a reasonable predictive model that could confidently predict
> whether a given passive orthotic helps or hurts and how much.
> There are exceptions, for example we could confidently
> predict that plyers and levers help increase the
> forces people can apply. But for locomotion I don't think
> we understand the mechanics well enough.
> Many pros and cons we can list, of course, as others have
> done already in answer to your question. And this understanding
> will help motivate new designs. But knowing ahead of time,
> without experiments on people, what will help or hurt and how
> much is more than the state of the art. At least as it looks
> to me.
> `Scientific' claims on either side are not credible.
> That muscles can give back more work than they absorb
> is a nonsense explanation of how muscles make things
> easier/faster than synthetic springs. That springs
> are necessarily helpful is also not informative.
> But there is a scientific answer.
> Empirical measurement and statistics are science.
> Once there is a data base then we will see whether springy
> orthotics let amputee athletes, on average, do better than
> athletes with feet. Even one guy might provide suggestive
> statistics. If one guy all of a sudden brakes
> lots of records by a lot, even an n of one, would be pretty
> indicative. That is, if this one guy gets a gold medal
> it means he's pretty special. And since there is something
> conspicuously special about him, his feet, that would be
> the likely (though not assuredly) best explanation. That
> is, if I was the judge, this guy would have trouble
> convincing me that he was the "best" athlete even if
> he is, which he seems to be, incredibly good. He could
> be _the_ best, but that is not what occam's razor would
> say. And I don't see any 'science' that would make a better
> case.
> My personal guess is that in the coming years, with orthotics
> some people will gain a speed advantage in running,
> even if starting with a disability. Why not? Would
> one doubt that a double BK amputee could swim pretty
> fast with fins? Why should running be so different?
> About the ethics. All competition is unfair, the better
> one's have an advantage. To make the outcome less
> predictable, to give more people a chance to win,
> to make it more of a challenge for all, sports
> officials put competitors in
> bins that have historically been shown to be
> predictive, e.g., by sex (men vs women), by weight (heavyweight
> vs lightweight), by number of people (1,4, or 8 in
> a boat), by age (youth vs adult), and even by ability
> (major league vs minor league). Once there are a lot
> of carbon foot runners that run, on average, faster than
> skin-and-bone runners there can be a class for them too.
> In the mean time, I hope they let the guy run and see
> how he does. "Fair" or not I don't know, but an inspiration
> for biomechanics and orthotics for sure.
> -Andy Ruina, ruina@cornell.edu, http://ruina.tam.cornell.edu
> Universal phone (SkypeIn, works wherever I am): 607 821-1442
> Finland cell: +358 40 872-6255 (+ means dial 011 from USA)
> On May 17, 2007, at 1:25 AM, Ajit Chaudhari wrote:
>> -----Original Message-----
>> From: * Biomechanics and Movement Science listserver
>> [mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Ton van den Bogert
>> Sent: Wednesday, May 16, 2007 10:59 AM
>> Subject: [BIOMCH-L] amputee sprinter
>> Yesterday's New York Times had an article about a double amputee from
>> South Africa who runs 100 m in 10.9 seconds and appears to be still
>> improving.
>> There is debate whether he should be allowed to run in the 2008
>> Olympics, if he qualifies.
>> The IAAF says that his energy-storing feet are an unfair advantage.
>> Others say they are not, since they only return 80% of the energy.
>> There are
>> calls for further research.
>> The athlete, Oscar Pistorius, said "I think they're afraid to do the
>> research. They're afraid of what they're going to find, that I don't
>> have an
>> advantage and they'll have to let me compete."
>> What do the Biomch-L subscribers think? I know we have some
>> subscribers
>> who are experts on this topic.
>> The full article is here:
>> http://www.nytimes.com/2007/05/15/sports/othersports/15runner.html
>> Ton van den Bogert, Biomch-L co-moderator
>> http://www.Biomch-L.org
>> ---------------------------------------------------------------
>> Information about BIOMCH-L: http://www.Biomch-L.org> www.biomch-l.org/>
>> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
>> ---------------------------------------------------------------
> ---------------------------------------------------------------
> Information about BIOMCH-L: http://www.Biomch-L.org
> Archives: http://listserv.surfnet.nl/archives/Biomch-L.html
> ---------------------------------------------------------------