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Tuesday, July 17, 2007

Oscar Pistorius debut: the scientific facts and implications, UPDATED

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!

So this weekend saw the much anticipated and much debated debut of Oscar Pistorius, South African Paralympic runner, in the 400m events at the Rome Golden Gala and a Sheffield Grand Prix. And unfortunately, the weather intervened in Sheffield and we perhaps did not see the best of the runner, making interpretation of the IAAF data difficult.

But there was Rome, and a time good enough in the B-race to gain second place, finishing in 46.90, which is about half a second off his PB. And the IAAF did analyse this race, with some fascinating results. Some of these results were published in the Sunday papers, and members of the IAAF have been giving interviews and explaining their results. In one of the local papers down here in SA, they actually reported some of the results from the IAAF analysis in Rome, and so using those facts, and together with some other really interesting data from other 400 m races, thought it might be interesting to do a post to investigate the theories.

Note that this is not all the research that will be done, and nor is it even a comprehensive discussion on the small part that has been done, but I thought it would be interesting to look at the factors that need to be considered, so here is my interpretation.

On Friday night, while I was watching the Rome event on TV, it occurred to me that the 400 m events are all about survival. Because the race is really won or lost in the final straight. The athletes seem to seize up, and get incredibly tight and slow down progressively. And science has shown us that athletes get slower and slower as the race progresses. This is even the case for the world record of Michael Johnson, and for the winning performances of every single 400 m Olympic champion. Fast start, slower finish, and the winner is the one who slows down the least.

Why does this happen? Well, it's complicated, but the basic reason is that fatigue impairs the ability of the muscle to store and release energy and to provide forward propulsion. Remember, an able-bodied runner has to invest ene
rgy twice - once to store the energy and again to release it. These muscle contractions cause changes in the muscle, they have a cost and this cost is ultimately what causes the athlete to slow down - whether this is muscular or nervous system is not really relevant to this discussion.

But what happens if part of the leg never gets tired? I
f there’s no muscle to reduce activation levels of? Because then the athlete is benefiting from forward propulsion without the possibility of fatigue. If this is true, then the prediction is that the that an athlete running on Cheetahs will start and finish at much more comparable speed than anyone else.

But what does the science show? The gra
ph below shows the average time taken to run each 100m interval in 8 world-class 400m runners. These were runners in the FINAL OF THE WORLD CHAMPIONSHIPS EVENT IN 1999, so they're the best of the best (this data was taken from the IAAF Journal - New Studies in Athletics, vol. 16, 2001)

What you will see immediately is that the runners slow down progressively over the course of the race. This group even includes a world record from Michael Johnson, who ran 43.18s and was no different to the other guys. In the meeting in Rome the other night, the winner of the A-race, LaShawn Merrit, ran the first 200m in 21.2 and the second 200m in 23.3 secs.

So what we see right away is that there
is ALWAYS about a 2-second difference between the first and second half of the race - the first 200m is 2 seconds faster than the second 200m.

So now you take a look at a graph below, that shows the difference between the first and second half of the race for 16 atheltes - men and women's finallists at the World Champs in 1999. What I have done here is to subtract the time for the second half from the time for the first half. Here, if the athlete has run the first half faster (as they always do), then the value will be negative.
(Data from IAAF New Studies in Athletics, vol 16, 2001)

However, there is ONE value that lies well outside these others. And this is the value that you get when you look at Pistorius' halves against the able-bodied runners in Rome. These times, measured off the cameras filming the race, and reported in the media over the weekend, show that Pistorius does indeed have the ability to finish the 400 m faster than any other runner relative to the first half. That was actually obvious when watching the race and reading reports. In fact, one might go so far as to say that Pistorius' second half may be faster than most other 400 m runners in history. So having lost the time in the first 100m, he seems able to make up most of it and avoid the fate of all the other runners who slow down over the second half of the race (Note: I read in an English paper that the splits from Sheffield were 24.4/23.3, so the same pattern was followed)

Many of you are no doubt thinking sure, but his slow start, a problem which has been acknowledged, explains why his first half is slow. The start probably costs him about 1 second though, so you can move this red block down by about 1 second, and you have a difference of +0.5 secs, which is still a major one considering that NO ONE IN HISTORY has run a decent 400m race with this pattern.

So the next question is whether this is because of a slow start or a fast finish, and that requires further analysis. However, in the interest of allowing the IAAF to do their work, it would not be proper to publish those results until there is at least permission, so unfortunately, we'll have to speculate a little bit until a later stage.

What the data do show is that there may be a massive energy saving in the last part of the race, as has been described. If the prosthetics were less energy efficient, this would not be possible - if anything he'd slow progressively as the distance increased. Fact is that at the very worst, he has maintained speed for longer, sped up more, and slowed down less than any other runner. And the second half is faster than most runners in history as a result, even when running 44 seconds or faster. In fact, the only second half faster than this out of the other 9 atheltes analysed was Johnson when he broke the world record - he ran the second 200 m interval in 21.96 secs.

So what does this mean? Well, it's not proving anything, but it's strongly suggestive of some sort of second half benefit, because it's physiologically impossible to run these sorts of splits. I will grant that it also shows that the slow start is a significant disadvantage, but there has never really been a question of this. The second half, however, is in-line with predictions made by the theoretical arguments and models for his performances.

There is no doubt more data, even more interesting, but I guess that this will have to wait until the research is completed and then released to the media. But the data they have gathered so far, in my opinion, are highly suggestive of some sort of effect, particularly in the second half of the race. What is left for the IAAF to do is decide on the next questions they need to evaluate, and while I again can't go into the details, they have some very intriguing information to pursue.

We'll try to keep you posted, and as soon as it all comes out, we'll definitely give the full scientific run-down on whether or not the limbs might be advantageous, and why (or why not).

R & J

Over the coming weeks, as the IAAF make the results available, this article will be updated to cover all the findings.

See also:

Evaluation of the scientific debate around Oscar Pistorius: Science & Engineering vs Training

Open letter to the IAAF: Research on Pistorius

Oscar Pistorius: Should he be allowed to run?


Unknown said...

Nice one - definite food for thought. I'm still up in the air over this one.

Anonymous said...

I really liked this post. You brought a fresh, insightful, and certainly scientific approach to evaluating one of the many aspects in which Oscar may receive a benefit from his "Cheetahs."

I have publicly stated that I thought Oscar should be given the benefit of the doubt until it is proven that his blades give him a distinct advantage. My reaction to this story when I first heard about it was that there was a gut reaction to ban him without doing any actual research. I grant that he may get distinct advantages from the blades, but to discount the hard work and training he's put in and claim his success is the result of technology alone was a claim I found many people making, though I never got that impression from your posts.

Anyway, I think you add some great food for thought to this debate. I have no doubt that we will learn a lot of interesting things about Oscar Pistorius' advantages and disadvantages over the next few months. What I doubt is that we'll ever be able to tell conclusively if one outweighs the other...

Ross Tucker and Jonathan Dugas said...

Hello Scott and Bryan

Thanks for your comments and feedback, much appreciated.

Bryan, i agree that in the end, we'll never really know conclusively that one outweighs the other, but I guess the biggest problem looking forward is that if there is any advantage (which I think the data suggest there is, once he is up and running), then it can always be improved, and the disadvantage can be reduced, until it does eventually happen that the advantage outweighs the disadvantages.

So basically, I think that the debate should actually centre around whether there is an advantage - the disadvantage is another story, because there certainly are some. But provided those advantages exist, then authorities can't allow him to run, because future developments and advances will see us to a sub 40 second 400m time.

Thanks again!

Anonymous said...

My son has bilateral fibular hemimelia and you are missing some very important pieces of information concerning why people with this disorder can excel as runners. Its not as complicated as you think, and only Oscar's camp knows the whole story.

Ross Tucker and Jonathan Dugas said...

HI anonymous

Thank you very much for the email. I am very interested in the details of what you say.

I actually think it is fairly simple myself, but there are many issues that could complicate matters, and these are what arose during the course of discussing the issue here and elsewhere (TV interviews, discussions and debates with the Pistorius camp), and that is what I addressed.

But I really am very curious about what you have said, and I would like to learn more about this, so if you have time and opportunity, and if you would like, please feel free, I am very willing to listen. You can also email directly to sportsscientists@gmail.com

Thank you very much for visiting the blog.


Anonymous said...

Hello everyone!! This is professor Diddle. I would just like to state that I am doing a research project on Mr. Pistorius. He is a wonderful athlete. Please help me with me research.

Thank you,
Professor Q. T. Diddle