Oscar Pistorius: My Views......

"Pistorius gets power from other muscles in his body, all of which fatigue normally."

I have a runner friend who lost her leg just below the knee. She has done much research on the effects of amputation on muscle fatigue, and it appears that the compensatory muscles DO NOT fatigue normally. From a strictly physical standpoint, no amputee can likely make up for deficits caused by the amputation with any sort of prostetic device. Furthermore, the abnormal giat that many amputees adopt to help overcome "energy deficit" can easly lead to injuries elsewhere'

Please see the following:

"People who have undergone amputations have incorporated different muscles and adaptive strategies to ensure a smooth and well-coordinated gait pattern. An important concept must be remembered in analyzing any pathologic gait (including the gait of those who have undergone amputations): An individual's gait is optimized to use the least amount of energy to cover the greatest distance.

Several factors need to be accounted for when thinking about the energy costs of prosthetic ambulation. One is the actual metabolic costs (peak exercise oxygen consumption [VO2] in mL/kg/m) of the person who has undergone amputation compared to that of intact people. That is to say, metabolic cost is measured based on the metabolic oxygen consumption in relation to the distance walked. Clinically, metabolic cost is a gauge of endurance. In the healthy intact person, walking is more efficacious at self-selected walking speeds. The metabolic cost rises at slower or faster rates of ambulation. Comparatively, persons who have undergone amputations exhibit the same correlation of metabolic cost and ambulation speed with the metabolic costs exceeding the norm at any given walking speed. The increase in metabolic cost for persons who have undergone amputations means the gait is inefficient compared to that of healthy intact persons, who require less endurance for any given distance. Those who have undergone traumatic transtibial (TT) amputations use at least 25% more energy during gait, whereas someone who has undergone a vascular TT amputation has at least a 40% increase in energy expenditure. A person who has undergone a traumatic transfemoral (TF) amputation uses at least 68% more energy during gait, while a person who has undergone a vascular TF amputation uses at least 100% more energy.

A pathologic gait is an inefficient mode of locomotion that usually requires considerably more energy than a normal gait. Patients may adopt many kinds of abnormal movements to minimize their energy usage. Two methods of energy optimization exist: those involving energy transfers and those involving movements that minimize the displacement of the center of gravity."

The whole link is herre and is very interesting reading:

http://www.emedicine.com/orthoped/topic633.htm

Advantage Pistorus? I don't think so.

RB

I don't quite understand why his legs were amputated in the first place. Many times you will hear people claim the various evolutionary paths humans will take in the future. Often, fibulas disappearing is one thing mentioned. Apparently we don't really need them and in some people they are like splint bones in horses. They are just free floating with little or no attachments.

Surely there is more to it than the articles mention but they make it sound like if he was missing an ear they would have cut his head off.

This debate is covered in the discussion around the original articles. And as I have mentioned numerous times in this thread, there is an argument to be made for the double amputee having a HIGHER cost of running than an able-bodied athlete. So if you go back on the thread and read the post, you'll see that there are effectively two models - one says higher energy cost (your argument, explained above), the other suggests lower energy cost.

Now, the data that the IAAF have collected can be used to evaluate the models - quite clearly (and correct me if I'm wrong), if the cost of running is HIGHER, then he would have to slow down more than the able-bodied runner, because the metabolic cost is, after all, the thing that causes him to slow down in the first place. That would be like comparing an efficient athlete to an inefficient one - the difference is manifest as the time of exercise increases.

However, the energy cost is LOWER, then the model predicts that he would be able to sustain the same speed. And that's exactly what happens. So I hear your argument, it needed to be considered, but it's not been confirmed or even suggested by the observation. And if you really think about it, to suggest that the energy cost is 25% higher, you are saying that Pistorius is actually 25% better than the able-bodied runners he wants to race against. Even if only 25% of the performance could be accounted for by energetics (which is an underestimate), then you are saying that Pistorius should be capable of running 6% faster, which is 12 seconds - so that means we are watching a 36 second 400m runner! That's logic I'm sure will be questioned, but the numbers might be questioned, but the logic is there.

The other thing you are perhaps missing is that all these studies have been done examining non-running prosthetics. There are massive differences between these non specific prosthetics and the running ones, like the Cheetahs. So the very latest work, which was presented at the ACSM conference in June, showed that the running prosthetics are able to reduce the difference in economy between able-bodied runners and amputees - the difference disappeared at 8 miles/hour pace. Now as the speed increases, the Cheetahs will provide even more recoil and return of elastic energy. That's how they've been designed. So all this means is that there ia ctually scientific evidence that the RUNNING prosthetics, which are specially designed to propel the athlete, store energy, create extra bounce, built in shock absorption etc. are actually better, even from a data point of view.

So your studies are correct, but you have to realise that they are different, and that difference, is, to be redundant, the difference!

One final thing is that anyone who loses a limb/s after learning to walk will probably never be able to learn to sprint. Again, this has been said on the forum already, but it's worth repreating - the motor control of the limbs is probably too complex to RELEARN, and so for anyone who has to learn to walk AGAIN, the complexity is what causes the abnormal gait. Now, if you learn to walk on prosthetics from a young age (try one year), AND you have a physical therapist to train the 'bad habits' out of you, then you are in a postion where all these differences are minimized, if not removed completely.

So the point is that a lot of research that you cite and have linked to is correct, but this is a competely different scenario - you just have to look at the pacing of that 400m race to realise that.

mg wrote:

ross, i just wanted to thank you for spearheading probably the most informative, professional and well-thought out thread i ever have seen on here. your posts are extremely enlightening. however, i have not seen any information regarding what kind of aerobic engine OP has, if there is some minimal baseline for world class 400m runners and if he differs from that. for example, if he were a 5000m runner and his vo2max was 50 but he was running 13:20s, then i think that it would be safe to conclude that his legs were aiding him much more than normal legs (because no able-bodied runner with a vo2max of 50 could run anywhere near a 13:30).

Thanks MG, I'm flattered, though others started the thread and have made more telling points I'm sure. I just got to throw out some science terms!

To respond to your question, it's more complex than it might seem, though I'm sure you know this already. The biggest problem is that oxygen consumption (VO2) is probably not a large contributor to 400m performance. of course it is important but not as relevant as it would be in your example, the 5000 m. Even there, it's quite easy to tell two guys apart when they lie on the extremes of the continuum. So let's say you have Bob who has a VO2peak of 60 and Fred, with a VO2peak of 80. Good chance that Fred is the better runner. That's a 'no-brainer'. But once you get down to a comparison of maybe 68 compared to 72, then you have a problem. I'm sure you've seen studies, for example that have looked at elite runners and then suddenly VO2peak becomes less of a predictor, because factors like running economy are important.

So the problem in this debate is that we're likely to be lying on the bunched up part of the spread to begin with and then also, the 400m event is different because of the relative intensity.

I haven't actually seen data from Pistorius, and nor do I know if it even exists. Remember, the usual assessment for VO2 peak is a continuous running test, usually lasting between 10 and 15 minutes (minimum), and this would be quite difficult on the Cheetahs, on a treadmill. So it might be one of those hypothetical questions, unfortunately. The other option might be strength tests, but how do you assess the squat strength of a double-amputee? So direct comparisons are difficult. Perhaps someone out there can shed more light on this one, but in my opinion, the measurement is difficult, even though it might be relevant to measure.

Thanks for the feedback!

Ross

Ross,

This is great information you are sharing.

Sorry if this has been asked before, but if I understand you, and Pistorius does not slow in the 2nd half of his 400, then what are the implications for 800m performance? It seems to me that this would be a simple and telling test. If he can run an 800 with little or no slowdown from his 400 speed it seems clear tht he is getting an advantage (at least for these longer events). Has Pistorius ever run an 800? What about other amputees? What are their relative performance curves for 400 and 800 meters?

Thanks, Ross. I'll go back and read your earlier posts on the subject. And, I must admit to not knowing much about prosthetic technology, so that info was great. Perhaps what I posted does not apply in Pistorius' case. Not sure we'll ever have a definitive answer.

RB

Mr. Obvious wrote:

Ross,

This is great information you are sharing.

Sorry if this has been asked before, but if I understand you, and Pistorius does not slow in the 2nd half of his 400, then what are the implications for 800m performance? It seems to me that this would be a simple and telling test. If he can run an 800 with little or no slowdown from his 400 speed it seems clear tht he is getting an advantage (at least for these longer events). Has Pistorius ever run an 800? What about other amputees? What are their relative performance curves for 400 and 800 meters?

Good point, I don't think he's ever run an 800m. He made his 'debut' in Athens, and there he only did the 100 and 200m races, and I remember even then, it was quite clear that if he stepped up, he'd be more competitive, because he was losing maybe a second at the start and still running 11s and about 21.5s, so it was always going to be the case that running the 400m would give him a chance.

So the implications are that his 800m would be even better, so your test might be valid. Problem is, it's not quite as cut and dried as this - the logic doesn't always extend 'linearly', in that the runner doesn't just keep getting better and better, because there are other contributors to performance. Perhaps the duration of 1:45 is just too long for him, maybe he hates the idea of running that long. And the training is subtely different, as I'm sure all the readers are aware - the 400m to 800m transition is really tricky, it's easier to go 1500m down to 800m (think Coe, Ovett, Cram etc.). I hear shouts of Juantorena, but he was the exception.

So the physiology is pretty complex, and that still exists, make no mistake. It's not like Pistorius is immune to fatigue and could run a marathon at the same speed as he runs 400m! (Anyone care for a 1:20?). If this logic were correct, then Michael Johnson would have been a sub 1:40 - 800m runner. His result is in that article by the way - he is runner number 1 in the second figure, he ran his world record of 43.18s with splits of 21.22/21.96. So that's the most evenly paced "fast" 400m I know of (fast is subjective, I know,but let's call it within 2% of the best). So would he have been the greatest 800m runner ever? In theory, perhaps...but that's a rhetorical question!

But, yes, I suspect his 800m performance would be slightly better, relative to his 400m one. Whether he could do the necessary DISTANCE work is another question...

Who said life was fair....

VO2 tests need not only be done on a treadmill. They have definitely done them with the athlete running on a track, and the researcher alongside in a golfcart-type vehicle. I've seen pictures in older running book (maybe Coe/Martin?)

How about using stem cell to grow new legs?

They can create new ears, hearts etc. These would be from the same genetic make-up.

Or create a clone.

Stupid examples, but perhaps the only way to create a full-body?

In reality, I would promote OP whereever possible as a great athlete and a bridge between Olympics and Paralympics. Should he be able to compete in Olympics / World Champs, probably not.