Welcome to the Science of Sport, where we bring you the second, third, and fourth level of analysis you will not find anywhere else.

Be it doping in sport, hot topics like Caster Semenya or Oscar Pistorius, or the dehydration myth, we try to translate the science behind sports and sports performance.

Consider a donation if you like what you see here!


Did you know?
We published The Runner's Body in May 2009. With an average 4.4/5 stars on Amazon.com, it has been receiving positive reviews from runners and non-runners alike.

Available for the Kindle and also in the traditional paper back. It will make a great gift for the runners you know, and helps support our work here on The Science of Sport.



Monday, November 23, 2009

Oscar Pistorius gets a 10 second advantage in a 400m race

Welcome to the Science of Sport. If you are looking for the VERY LATEST discussion about the research on Oscar Pistorius' advantages ahead of the Daegu World Champs,  please read THESE ARTICLES:

  1. The first study - the IAAF find "bouncing locomotion at lower metabolic cost"
  2. The second study - how Herr selectively ignored data to make Pistorius look more similar when the evidence said massive differences and advantages existed
  3. The mechanical advantages that explain why Pistorius has a running advantage
The article below was written in 2008, but has been "dated" by the latest publications by Weyand and further debate on the issue.

Thanks for visiting!
Ross

***Note to visitors looking for info on the Caster Semenya debacle***
Please see our other posts we have written in covering that story:


10 seconds over 400m - the magnitude of Oscar Pistorius' advantage in a 400m race

If you did a double-take as you read that headline, you're not alone.  About three hours ago, I received a phone call from a radio station in Canada asking my opinion on this latest research finding.  I had not even heard of it, having been in meetings and presentations all day.  Yet there it is - an article that will be published tomorrow has the startling conclusion that Oscar Pistorius, the self-styled Blade Runner, "runs the distance 10 seconds faster than he would if his prosthetic limbs behaved like normal legs"

The actual discussion and research findings and interpretations will be published in the Journal of Applied Physiology tomorrow, and I'll definitely be quicker getting to that one, and will post more on it then.  But for now, I have to throw out some thoughts on this latest revelation, which has clearly taken me by surprise, though not because of what it finds, but rather because of who is suggesting it and based on what it is suggested.

First though, allow me to apologize for my 'silence' in the last week.  I arrived back in SA last week, and then found out that I will be traveling with the SA Sevens Team to Dubai next week, which is obviously a huge honor for me, but has meant that I have 6 weeks of missed work and 4 weeks of upcoming work to condense into two weeks!  So the last week has been busy, but this latest story had to be commented on.

Pistorius' 10-sec advantage - according to the sum of the research

So let's cut right to it - the statement you see above, that Pistorius has a 10 second advantage in a single 400m race, was made by two of the scientists who did the testing that cleared him at the CAS hearing in 2008.  That's right, the research that was presented by the science and lawyers to allow him to compete against able-bodied runners has now been interpreted to show that he enjoys what amounts to an advantage that is, quite frankly, large enough to turn a merely decent high school runner into a world class 400m athlete.

You can read the press release here.  The author quoted is Peter Weyand, who was part of a team who Pistorius contacted to help build the case that he did NOT receive an advantage thanks to the high-tech carbon fibre blades.  Some of the talking points from the release, which I'll hopefully bring up again in the future, include:
  • “Pistorius’ sprinting mechanics are anomalous, advantageous and directly attributable to how much lighter and springier his artificial limbs are,” Weyand said in a statement. “The blades enhance sprint running speeds by 15-30 percent.”

  • "We are pleased to finally be able to go public with conclusions that the publishing process has required us to keep confidential until now. We recognized that the blades provide a major advantage as soon as we analyzed the critical data more than a year and a half ago (my emphasis)"
The main reasons for the advantage, incidentally,  relate to the mass of the blades, which is substantially reduced, and allow Pistorius to reposition his legs much faster.  Added to this is the elastic property of the blades, which allow reduced energy cost of running, increased energy return, and of course, reduction in fatigue over the course of a race.  But more on this in the future, hopefully. 

"New evidence" that has been around for a while

Now, there are some pretty big questions about the process that jump to mind here.  Firstly, if the analysis of the data "more than 18 months ago" suggested that there was an advantage (Weyand's own words, because I know a lot of people have been critical of me for suggesting this since the whole issue began), then how did the CAS NOT see that data or at least hear the possibility when they had to make the decision?  This is not "new" research, it's just newly released.  

And while it's only being published now, it seems to me that this possibility has been known by those intimately involved in the case, but not disclosed, when it needed to be.  Why not?  The CAS process in 2008 disregarded the entire peer-review process in the lead-up to the judgment.  They clearly did not consider all the evidence, but framed a very specific question regarding the IAAF research.  Whether the research was published or not was irrelevant to the CAS back in 2008 when they cleared Pistorius.  So saying the finding was not published is not an excuse for not disclosing it back then.  The result was a verdict based not on truth, but selected manipulation of opinion, by scientists, lawyers, or both.

Inconsistencies in the process

I have maintained from the outset that there is an advantage, as regular readers are well aware.  I even threw out a figure of 5 to 6 seconds, based only on coaching information and knowledge of the local running scene.  The theoretical basis for this advantage has been discussed over and over on this site (you can read the stories at this link - just select one of the many Pistorius stories), and I won't go into it again here.

However, take a look at what was said 18 months ago, in a press release issued around the time of the CAS verdict.  Note that this came soon after the decision, and was done to throw scientific weight behind what was said at CAS:

"Based on the data collected at Rice, the blades do not confer an enhanced ability to hold speed over a 400m race," Weyand said. "Nor does our research support the IAAF's claims of how the blades provide some sort of mechanical advantage for sprinting."

How can these two statements be reconciled:
  1. "Based on the data collected at Rice, the blades do not confer an enhanced ability to hold speed over a 400m race" (16 May, 2008)
  2. "We recognized that the blades provide a major advantage as soon as we analyzed the critical data more than a year and a half ago," said Weyand and Bundle in a statement (17 November, 2009 - both refer to the same time period)
I am amazed.  I suspect, given the nature of science, that this may revolve around the nature of the question being asked, and the 'burden of proof' to show that the advantage existed.   The legal process ended up creating a situation where the IAAF evidence had to be evaluated, and that was all.  Refute the evidence, win the case.  No need to actually find the truth.  It was the sports science equivalent of a technicality.  However, the point remains that there was clearly a differing view, one that was never offered, either deliberately or by accident, and that is wrong.

Then there is the issue of scientific disagreement, which happens all the time.  Indeed, the Weyand article in JAP tomorrow is a counterpoint article with Hugh Herr, who was another of the scientists involved in the research process.  This suggests that one half are saying there is an advantage, one half saying there is not.  Such is the nature of science - different interpretations of the data happen all the time.

But this only serves to emphasize that the decision should never have been made the way it was, in the absence of this very debate.  The scientific peer-review process serves to bring out the truth, whereas what transpired at the CAS did not - at best, it failed to reveal all sides to the scientific debate.  At worst, it allowed them to be deliberately buried.

And the subtle changes in question are good and well, but let's be straight - the CAS should have evaluated the question that Weyand has very clearly admitted suspecting an answer to 18 months ago.  Yet all reports seem to suggest that the CAS was given a very different picture, a very different interpretation, and what I have maintained all along is that the wrong decision was made.  This does little to suggest otherwise.

Have we reached a satisfactory conclusion?

In my opinion, at least we've arrived at the right answer.  There are questions around the CAS process, no doubt.  Did the legal team win that argument?  Did Pistorius "buy" the verdict (note that I am not implying any financial incentive, since I believe none was involved.  However, the question remains, was there some manipulation behind the scenes?).  Were Weyand and Bundle 'silenced' until now in the name of Pistorius making dollars out of commercial sponsorships and science?  What went on that saw an "obvious" conclusion buried while "bad science" was propagated as "proof" of no advantage?

I can tell you how Pistorius sourced those experts - he effectively did the equivalent of "door-to-door" selling, because he approached every single university in SA first, and asked them to prove that he had no advantage.  I know this, because the big irony was that I was asked to look at his case in 2007 (by SA government, who he asked to help him).  I wrote back (as did a number of others) and said that there was an advantage, so we would not be able to assist.  Then he wound up in the USA, where he found a team who would do the research, and present it to the CAS.  What happened in between, I don't know.

Flawed research, flawed process, time to review

What I do know is that the research he presented was flawed, there were some fundamental problems with it, including issues around the timing of testing, the selection of the control subjects, and the basis for doing some of the tests.  I wrote about these in a previous post.

However, this latest paper, and Weyand's quotes, suggest something bigger in play.  I will confess that I am relieved to finally hear another scientist speaking openly and definitively (to the degree that they're actually claiming a time saving in a race) about this topic.  It has been long overdue.

But for now, I'm still amazed that this knowledge has seemed to exist for 18 months, but legal decisions have been made,  and 'definitive conclusions' have been reached.  This is the reason that the CAS verdict should NOT have been made until peer-review, discussion and the opportunity for many people to examine the method and results of the research.  It was clear in 2008, and it has been exposed now. 

So Pistorius did a smash-and-grab at the CAS in 2008.  Nothing new there.  The big question now is whether the right thing will be done and this 'latest evidence' (which is actually 18 months old) will be used to reverse that decision, or whether the decision is binding.

The point is that even if Weyand is wrong, and the advantage is 5 seconds instead of 10 seconds, that's enough.  It's a massive advantage, the kind that turns a mediocre club runner (51 seconds) into an Olympic hopeful.  And the fact of the matter is, that should be disallowed, because someday, a good runner (46 seconds) will run in the high-tech blades, and the 40-second barrier will fall.

Time will tell.  More to come, once the JAP paper is out and I've seen it.

Ross

26 Comments:

Steven Sashen said...

I haven't read the research behind this article in our local paper... but for a differing view, overall:

CU-Boulder study: No advantage for runners with prostheses

mcgrathe said...

Great news to hear this, but as you say it raises huge questions about the credibility of the CAS investigation.

I suspect that the original quote "Based on the data collected at Rice, the blades do not confer an enhanced ability to hold speed over a 400m race" will be justified by a technicality - perhaps they will argue that the advantage conferred by the blades is not "an enhanced ability to hold speed" but some other form of advantage which effectively equates to the same result.

As you mention, all they seemed to do was disprove the IAAF's proposed mechanism - essentially saying "You're right, but you don't know why you're right so he should still be allowed to run"

I await developments anxiously.


On another SA note, any more comments on the Semenya case following the last few developments - Cheune's admission and suspension in particular?

Bobd said...

I'm sorry about all the people that this will offend, but the reality is that this whole case is just another example of the bleeding heart altruistic left trying to inject their emotional position into everything science be damned.

It is no different than when they allowed Casey Martin to ride his golf cart in PGA tournaments and the whole unscientific BS about man made global warming caused by carbon dioxide. Allowing Oscar to compete with elite runners is no more scientific than computer models are that blame carbon dioxide for man made global warming. It's all politics and has no basis in reality.

Dudley Tabakin said...

I am not sure that the Weyand et al. argument is all that conclusive. It is interesting to read the counterpoints discussed by Dr Rodger Kram. http://jap.physiology.org/cgi/reprint/01238.2009v1

Weyand is giving his opinion, not surprisingly based on past research that he has done in the field of sprinting. One of his articles is "Faster top running speeds are
achieved with greater ground forces not more rapid leg movements", which contradicts his point that Pistorius can run faster because he is able to reposition his legs 15% faster than recent 100m World Record holders.

More research is definitely needed to put this one to bed. Studying one bilateral amputee athlete, who has probably modified his gait to run with artificial limbs is not good enough to make this type of conclusion. In saying this , I still believe that artificial limbs do provide the advantage to the amputee over an able bodied athlete, particularly in the longer sprint races.

Ross Tucker and Jonathan Dugas said...

Hi Steven

Thanks for the post - good to hear from you! I'll respond to your other email separately!

I saw that study. I was astounded that they'd apply the findings of a study on single leg amputees to a double-limb amputee. Completely different mechanics, and, according to Weyand, largely irrelevant, because the advantage is not on the ability to exert force on the ground. So I don't know if the media portrayed the single-leg study in that way, or if it was the CU researchers, but it was shameful exploitation. It was like taking cross-country skiing and comparing it to running as far as I'm concerned, so different are the mechanics.

It seems clear to me that there is something up with the researchers, because that point-counterpoint in JAP degenerated into a rather angry argument by the end, accusations of disrespect being lobbed about. SO I don't know what's gone on with the scientific team, or when the 'split' occurred, but it just seems to me that decisions have been made with only partial disclosure.

So as Mcgrathe, Bobd and Dudley have all alluded to, there is something missing from this picture, and the decision should never have been reached.

As for the arguments, Dudley, you're right, the point-counterpoint thing, which happens all the time, does represent two different interpretations of the same data. I remember being involved in one, related to fatigue and the role of the brain, and they end up going around in circles a little. Happens all the time. So I agree that there remains a question mark, but I just feel that this question mark should at least have been presented to the CAS 18 months ago, since it seems clear that this belief about his advantage has existed since back then. For some reason, it didn't surface when the decision was made, and that's bizarre.

Ross

Mircea said...

Yes Dudley, Weyand is a bit inconclusive in general. He does contradict himself with the two papers, but I would say the "Faster top running speeds are achieved with greater ground forces not more rapid leg movements" is insignificant and almost off topic. If you talk about swing time like he does you are only addressing half the equation of speed. What about the distance? Let's talk about the angular velocity of the limbs and see where we get.

+If amateur runners reposition their legs as fast as pro sprinters(at maximum speed) and O.P. 15% faster he is outside normal humans' range so therefore suspicious.

미르차

Sara said...

I can see how a prosthetic would confer an advantage, but it's sad that it's so dramatized. I am aware that 10 secs is a huge advantage in something like a 400m sprint( I recently lost by about 15 secs the other day to a friend on a friendly competition). However, as a soldier currently deployed, and an avid runner and lover of competition, my greatest fear is that I'll lose a leg and never be able to compete again because of the issues that people have with runners using prosthetics. Some sort of even ground needs to be found, because it's not fair to an amputee that their life and dreams are shattered because of an accident out of their control.

Lesser Idiot said...

bobd, computer models are not the main reason man is blamed for recent global warming, it is direct measurement of the isotopes of carbon in the atmosphere, which are unique to burned fossil fuels.

i more or less agree with your other sentiments though.

donncha said...

It seems that most of his advantage comes from the cheetahs being lighter than a real lower limb. Would it therefore be possible to insist that they be made the same weight, thereby negating almost all of his advantage?

Mike185 said...

Are there any photosequences available showing a side view of Pistorius in action? I'd like to see a comparison with the trajectories of a top sprinter.

G. John Mullen said...

Swimming bans suits that allow everyone a slight mechanical advantage, and track and field allows a bionic man who is gaining a 10-15% advantage...all sports need to start making clear guidelines for sports technology or debates like this will never subside.

_______________________________
http://swimscience.blogspot.com/

Richard Blalock said...

I have looked but have yet to find evidence of any WRs in running by amputees to be faster than their able-bodied competitors.

Not a single one.

Perhaps I missed this huge advantage, and blinked and lost Oscar blasting past LaShawn Merritt in Beijing and crushing the world record in the process.

Sometimes realty is all the science we need. And while we're at it, demand Al Gore give back his political prize.

- Richard Blalock
Amputee 4/14/2009
First race 11/14/2009

Ross Tucker and Jonathan Dugas said...

Hi Richard

I don't think you've missed Pistorius running by as you blinked, but I do think you've missed the point here.

The reason Pistorius has not beaten LaShawn Merrit is because he's not good enough an athlete to do it, simply put. If Weyand is right, then Pistorius is a 55 to 56 second 400m runner, who runs 46 thanks to the technology.

What you are arguing, that no amputees have broken able-bodied WR, is a simple argument too. A single-leg amputee will never be able to run as fast, because they are unbalanced as a result of different mass and length on the sides. That is key. I have spoken with the management of the US Paralympic team, and they say that the athlete is only as fast as his able-bodied side. Problem is, he's slower, because of the loss of balance

That's why some brilliant athletes are running around 11 seconds in a 100m in the single leg category. These are guys who might have been capable of 10 seconds.

However, a double amputee is a whole new story. The thing about Pistorius, which I'm sure you are aware, is that he learned to walk on prosthetic limbs, his learning process ensuring that he doesn't have the balance deficit that most people would have. Add to this that he participated in sport from a young age, that he had the money to afford expensive limbs and technology, and you have the ingredients for a why a double amputee is competitive.

My point is, the same arguments cannot apply to a single leg and double limb amputee. And when that double has had an entire life to master their use, then the result is an athlete who is not physiologically world class, but uses their equipment really well. That's the secret to Pistorius - the ability to use his equipment.

Ross

Richard Blalock said...

Ross,

Whereas I appreciate your thoughtful response, you have to make a huge, unscientific leap of questionable faith to state or assume Pistorius would be a rather common 55 - 56s 400m runner. It seems the argument presented here can have no real resolution because Oscar's able-bodied speed is impossible to determine. Guessing is not science.

I believe in (simple) reality, and given the large numbers of amputee athletes, that if your or Weyand's views were to be supported, there would be at least a handful of performances that would equal and likely crush existing able-bodied world records.

The human body is still a mystery in many ways. Many considered we'd never break a 4 minute mile, yet those brilliant minds had to face the reality of Sir Roger Bannister's feat. You cannot and will not know what Oscar Pistorius' able-bodied performance might be, you'd have better chances guessing the winning lottery numbers immho.

I have seen the stubby prosthetics Oscar learned to walk on, they have little to no relevance to the very different Cheetahs or even the most basic modern prosthetics of today. I do not yet have running blades, but I have been told they are a very different beast to master with little comparison to how I am running on my Renegade LP right now. "Night and day" difference is what Canadian WR marathoner Rick Ball has told me.

As an aside, most people won't - and I've already been asked about this - make a distinction between single and double leg amputees when it comes to running blades. To think my peers will think I have an unfair advantage goes a long way to ruining my love of running and competing.

Although I believe any such study may be flawed, perhaps considering athletes who have been able-bodied and lost their legs might at least shed some relevant light on the subject. Even so, the huge variance of aging could easily skew any result.

Before any such pronouncements of scientific fact are made, I think you better have definitive proof than the assumptions you are using to back up your finding(s). Few even knew Oscar was cleared to run as an abled-bodied athlete in Beijing, still remembering the so-called prior judgment of his mythical "advantage."

Have you consulted with MIT with their simple findings?

http://sciencenow.sciencemag.org/cgi/content/full/2009/1104/2?rss=1

Regards,
- Richard Blalock

Ken Jakalski said...

In Dr. Weyand's first statement:"Based on the data collected at Rice, the blades do not confer an enhanced ability to hold speed over a 400m race," I believe he was referring to the ASR test results, which showed that Pistorius fatigues just as sprinters with intact limbs would.

His second line: "Nor does our research support the IAAF's claims of how the blades provide some sort of mechanical advantage for sprinting" appears to be addressing
the actual IAAF 'case' against Pistorius, and the CAS's conclusion that: "the IAAF did not prove that the biomechanical effects of using this particular prosthetic device gives Oscar Pistorius an advantage over other athletes not using the device."

Now, were those statements simply 'compromises' to get all researchers to sign off on the paper? And in so doing did this allow for a specific "agenda" to be pushed forward?

Ken Jakalski said...

Hi Ross!

The following is an excellent point:
"I have spoken with the management of the US Paralympic team, and they say that the athlete is only as fast as his able-bodied side."

This is pretty much what Kram et.al. tried to establish in their counterpoint:
"We hypothesize that unilateral amputee sprinters run with equally rapid leg swing times for their affected and unaffected legs. If that hypothesis is supported, it would dispel the idea that lightweight prostheses provide a leg swing time advantage."

However, your counterpoint is spot on:
"I was astounded that they'd apply the findings of a study on single leg amputees to a double-limb amputee. Completely different mechanics, and, according to Weyand, largely irrelevant, because the advantage is not on the ability to exert force on the ground."

Ross Tucker and Jonathan Dugas said...

Hi Ken

Thanks for the comments you've posted.

To respond to your last one, I think so. It seems to me, based on what is coming out now, that there was some difference from the outset, but that the "technicality", or compromise, as you called it, allowed the initial research to be put out and interpreted by the media (no doubt 'aided' by some clever PR work).

Sure, it was a technicality, and they're now falling back on the issue that the initial statements referred only to the IAAF research, which was proven inadequate in the first round at CAS in 2008.

But to my mind, it seems that this evidence of an advantage has existed since the testing began, and how the process could proceed without full disclosure is beyond me.

It's either a cover-up driven by commercial interests, or a scientist who had an agenda (and here, Hugh Herr seems the likely one), or it's just a very flawed process, to allow a decision to be made on what are apparently very narrow terms!

Weyand's comments to Sports Illustrated (in my latest post) seem to indicate that he was unhappy from the outset, but that something kept the truth from coming out sooner. I'd love to know what that was.

Ross

Ken Jakalski said...

Hi Ross!

Were you surprised that the Grabowski paper, cited in the counterpoint piece,used swing time data gathered from a Beijing Olympics Highlight DVD to substantiate their claim that "low mass and inertia do not facilitate unnaturally fast leg swing times"?

I thought the Weyand/Bundle response was perhaps too kind when they noted the following:

"Low shutter speeds, frame-rates (30Hz), wide fields of view, and force-video offsets make television-estimated swing times highly uncertain."

At 30hz, it seems that the swing conclusions were based on someone clicking a remote on a standard DVD player. Am I missing something here?

Ross Tucker and Jonathan Dugas said...

HI Ken

I was surprised, but that's probably a consequence of the process. If this was anything like the usual journal "point-counterpoint" issue, then what would happen is that the first submission (in this case, by Weyand) is made, and the editor then sends it to the main protagonist for a response (Herr et al.), but that is time-bound.

I remember doing a similar one for a journal, and I had only a week to reply. This one may have been different, but I can't see it being too much longer. So they wouldn't have had too much time, and probably just dipped into the first resource that was available.

So that's the reason, but it doesn't condone that their defence was constructed around that. It came across as very amateurish, because what you say is true - they watched TV to counter the Weyand point.

Ross

Ken Jakalski said...

Hi Ross!

Thanks for that follow up. I understand the time constraints they were under, and I agree that they probably, as you noted, dipped into the first resource available. I'm just surprised that, since they knew from the outset how the argument was going to be framed, they weren't better prepared. However, without replicating the study and reaching a different conclusion, finding research refuting the 'advantage' claim might have been difficult. The McEnroe "are you serious" line, and the general tone of their last statement, really didn't make much sense coming from top notch scientists. It struck me as part spin, part damage control, and part frustration. But your overall analysis is probably more accurate: amateurish.

I can't wait to see how the rest of the research community weighs in on all of this!

Thanks again for your insights!

Anonymous said...

Hey- i am doing a report and am against this does anybody have anything to support this case?

Ross Tucker and Jonathan Dugas said...

Hi Anonymous

Not sure which position you're trying to argue. But there is plenty on this site - just go to the tabs on the top, and click on both the "2009 stories" and the "2008 stories" and you'll find plenty of articles on this case, with a lot of discussion of the key issues.

Regards
Ross

Anonymous said...

intresting ideas i think you have a ppoint but let's just say he can't so the other racers don't ask questions. depdown i know he should but somebody will always diagree so the public needs to do what i am doing in my report. chose a dicision because you have evidence and can back up even if your heart isn't entierly there. happy posting -anymous

Richard Blalock said...

The more I think about this, the more I see Weyand as the eternal optimist Floyd Landis; he has no real facts, yet it makes for good yellow journalism.

Still no world records to bilateral amputees even with their HUGE advantage over their able-bodied brothers.

Now if you can prove Oscar is running "tall" then I will agree he (likely) has an advantage over his peers (bilats) but other than that, I smell something very much amiss here.

Question: what is Oscar's turnover rate? Anyone? (Most elites run at 180 footstrikes/min.)

paddyR said...

This is an interesting area of study but there are a few keys points that seem to be ignored on both sides of the argument.

I have worked for a while in exercise physiology and must stress how important it is that in analysing human importance we consider everything that contributes to performace and not just one paramater such as mass, loading or recoil within a limb.

In sprint performance many things contribute to the runner attaining and sustaining top speed. One of these is proprioception/stability and the contribution it makes to motor unit firing in the active limb; especially in the foot and ankle during running. Obviously an amputee no longer retains this function.

With this in mind it would make sense, at least to me, that a useful place to start in this argument would be to propose a study looking at the role of stability and proprioception in sprint performance and then subsequently examine these parameters with prosthetic running blades. Systematic examination of parameters relating to running economy would follow this and the sports science community would then have the big picture about what may be the effects of using prosthetic running blades on performance.

I think this would be a more rational place to start the discussion as a lot data to date seem to ignore the fact that we're dealing with amputees who by definition have lost many of the important functions essential for running performanc that are taken for granted in many studies to date.

paddyR said...

This is an interesting area of study but there are a few keys points that seem to be ignored on both sides of the argument.

I have worked for a while in exercise physiology and must stress how important it is that in analysing human importance we consider everything that contributes to performace and not just one paramater such as mass, loading or recoil within a limb.

In sprint performance many things contribute to the runner attaining and sustaining top speed. One of these is proprioception/stability and the contribution it makes to motor unit firing in the active limb; especially in the foot and ankle during running. Obviously an amputee no longer retains this function.

With this in mind it would make sense, at least to me, that a useful place to start in this argument would be to propose a study looking at the role of stability and proprioception in sprint performance and then subsequently examine these parameters with prosthetic running blades. Systematic examination of parameters relating to running economy would follow this and the sports science community would then have the big picture about what may be the effects of using prosthetic running blades on performance.

I think this would be a more rational place to start the discussion as a lot data to date seem to ignore the fact that we're dealing with amputees who by definition have lost many of the important functions essential for running performanc that are taken for granted in many studies to date.