Analysing the argument: ‘long strides win the race’

Within minutes of being upset by Brazil’s Alan Oliveira in the final of the men’s T44 200m, Oscar Pistorius claimed he was “not running a fair race here”, the crux of his argument, which he also made ahead of the race, being that his rivals were artificially extending the length of their legs.

He said in an interview that “it’s very clear that the guys have got very long strides”, adding: “I can’t compete with Alan’s stride length.”

There is a lot more to running than stride length. If all it took was big strides, the running world would be dominated by the tallest men, and shorter runners like Tyson Gay would stand no chance. What matters is not just stride length, or height, but rather the length of the leg relative to height, and the ground contact length, which is, partly, a function of the leg length.

There is also force applied to the ground, leg turnover rates, etc.

Strides

Since Pistorius has emphasised the length of his rivals’ strides, I counted the strides.

South Africa's Oscar Pistorius is overtaken by Brazil's Alan Fonteles Cardoso Oliveira during their 200m final at the Paralympic Games on Sunday, September 2, 2012.

Press Association

It turns out Pistorius took 92 steps during the race (2.2m a stride), and Oliveira took 98 steps to win gold (2m a stride). In the first 100m, Pistorius took 49 steps (2m a stride), with 43 steps in the straight (2.3m a stride).

Oliveira, on the other hand, took shorter strides – 52 in the first 100m (1.92m each) and 46 in the second 100m (2.2m each).

Thus, a simple count shows that Pistorius has longer strides than Oliveira and that Oliveira’s faster speed is the result of faster leg movement. But the point here is that once again, there is this misinformation from Pistorius, and the media are too lazy to interrogate it further, but just report and allow the uninformed debate to go on.

Is it possible that the Brazilian has increased his stride length as a result of increasing the length of his blades? Of course it is.

This is part of the problem with the prosthetic limbs, and there’s no way to know this unless you go back to the IPC World Championships in 2011 and measure the height of the athlete and compare it to today.

You could count Oliveira’s strides and find that his stride length has increased, but now you have another problem – you can’t confidently attribute any increase to the leg length.

It may be that he has gained strength, and is covering more ground with each stride as a result.

If that were true, then his stride length relative to his height would be much greater, with no explanation other than many hours of good training.

So, for Oliveira, his improved performance may be due to the blade length, it may be due to his technical skill, it may be due to his improved strength, it may be due to some weight loss.

Only if his height was measured, and is continuously measured, can one know the answer with certainty.

But even then, an athlete may discover that he is a few inches shorter than the upper limit imposed by some rule based on ratios, and can, quite legally, add to his blades.

What is wrong with that? I’d say nothing – this is simply correcting and then optimising what nature did not provide.

The mistake was making the prosthetics too short the first time, and he should be allowed to add height within reason. This is another example of the slippery slope of sport technology.

What about the idea of an ideal leg length to match height?

The answer is that there is a range, but in elite athletes, the limits have to be wide because the ranges you’d find in the normal population don’t apply.

There is substantial evidence that elite runners (Kenyan and West African runners in particular) have disproportionately long legs relative to height, and so this may be a factor that predicts running success.

The double problem in a double amputee is that you don’t have a height – without prosthetic limbs, there’s no reference point against which to “anchor” leg length.

What about saying that “normal” leg length is a certain factor of the arm length?

That doesn’t work because the ranges are large enough to validate longer legs without violating the upper limit of what is found normally.

The bottom line is that whatever the rules of prosthetic limbs, if Oliveira is within them (and we have good reason to think that he is, given his compliance with the IPC and even Pistorius’s accusation is not that he is cheating, but that the rules are wrong), it just re-introduces the same debate – how do we know, with 100 percent certainty, that we are not seeing the result of some technological battle?

The answer is that we can’t. The leg length issue is an “advantage” that Pistorius has always had, and we’ve been watching him compete for years without knowing if he’s done the same thing he is now accusing Oliveira of doing.

And it does beg the question – why does Pistorius not just push his length up to the limit if the rules allow it?

Issue

The bigger issue is that of technology. The advantage for Oliveira was not his stride length, but his stride rate.

This is the factor Peter Weyand concluded gave Oscar Pistorius an enormous advantage over able-bodied runners who simply cannot move their limbs at the same rate, because Pistorius was able to achieve leg repositioning times that no able-bodied human ever could.

That advantage is still in play, except now we have another runner who is benefiting from it, and possibly exploiting it even better than Pistorius.

Are we just seeing the emergence of the next generation of athlete, equally capable of using the technology, but with greater athletic potential than Pistorius?

I’d be willing to say that there is already an athlete who has begun training who will beat both Oliveira and Pistorius by some margin and force these same questions, all over again.

If you’re wondering about whether Pistorius has a valid argument, then welcome to the slippery slope that is the introduction of technology.

* Dr Ross Tucker is a senior lecturer with UCT’s Exercise Science and Sports Medicine Department, and is on the management of the Springbok Sevens team, as a sports scientist and strategist. This is an edited version of an article published on the blog, The Science of Sport. The full article can be read at http://www.sportsscientists.com/2012/09/oscar-pistorius-counting-strides-as.html