Exercise in the Cold: Part I

Introduction to HYPOthermia and survival in the cold

As promised (a while back, admittedly), today we kick off a series on exercise in the cold. A challenging one to write, mostly because most of you reading this will (hopefully) never be exposed to conditions that are so extreme that your physiology is challenged to the point where it can't cope. Because most of you reading this are runners or cyclists, and it's only when you get into the water that a potentially lethal drop in body temperature is a real possibility. For the most part, exercise in the cold on land is limited by sensation and perceptions, which are of course controlled by wearing appropriate clothing. The biggest dangers of exercise in the cold on LAND? Frost-bite and other medical conditions, and not actually hypothermia.

But, there are still some fascinating studies and insights into exercise in the cold, and it is one of the most amazing areas of physiology to discuss. As I mentioned yesterday, Jonathan and I both worked with the polar swimmer Lewis Pugh when he prepared to swim 1km in the Arctic Ocean in 2005. Jonathan subsequently worked on his trip to the Antarctic as well. So we have a tendency towards COLD WATER physiology, which will make up the first couple of posts. Then we'll move onto the studies of running, cycling and muscle function during cycling and running.

So bear with us as we move through the series in a few parts:

1. How cold is cold? What are the limits to survival in the cold? Some stories of cold exposure in sport
   
2. The physiological responses to cold water immersion
3. The effects of cold temperatures on performance during swimming, cycling and running
4. Practical recommendations and insights

To begin with, how cold is "cold"?

In terms of body temperature, let's begin with a few basics - your body temperature as you read this is somewhere between 36 and 38 degrees - most textbooks will tell you 37 degrees celsius (or 98.6 Farenheit). As with exercise in the heat, the regulation of body temperature within a fairly narrow range is critical, not only for performance, but for health and survival. When we exercise, the body temperature very quickly rises to about 39 degrees celsius - one of the most remarkable questions in physiology, in my opinion, is why the body would allow this when it has the ability to lose the heat? It can reach 40 degrees celsius with few ill-effects, as found by numerous studies by the Danish group of Nielsen and Nybo.

The body regulates this temperature in a number of different ways. When we wrote about heat, we spoke of sweating, sending blood to the skin etc. In the cold, the opposite happens - you shift blood away from the skin, you shiver and release hormones that help keep the temperature up. The body is naturally insulated by skin, muscle and fat, and it's no co-incidence that on land and in water, the lean athlete, with low body fat percentage, is likely to get colder sooner!

What determines whether hypothermia happens ON LAND?

A drop in body temperature in recreational athletes is rarely seen ON LAND, even in quite cold conditions, provided they are not forced into prolonged exposure (discussed below). Rather, the main factor predicting body temperature is metabolic rate, and so provided you are exercising, your body temperature will rise, regardless of how cold it is...up to a point.

Remember that your body temperature will only fall if you lose heat faster than you produce it. When you are exercising in cold conditions, the fact is that you're usually:

• Dressed very warmly and therefore not likely to lose heat too rapidly - in this case, your body temperature is a function of heat production; or
• Dressed very inadequately, with skin exposed, or not waterproof. In this case, you'll FEEL so cold within minutes of starting, that you're likely to be unable to run altogether. You'll turn home and get warm in no time!

The point is, the SENSATION of the cold, mediated through your skin, precedes any fall in body temperature. So, by extension, provided you have free-will (and choose to exercise it - see the story of Andrew Wells below!), you'll be able to get warm without any complications. If, however, you're unlucky enough to get caught out, either because you're underdressed, far from shelter, or forced to spend a good deal of time in the cold (injury on the run/ride, getting lost etc. - think Polar explorers!), then your physiology really will be challenged, and that's what we'll tackle in subsequent posts!

Interestingly, in water, the situation is quite different. Because as we'll see tomorrow, you actually lose MORE HEAT when you exercise in the water than when you don't! So it's in water that hypothermia becomes a real threat - hypothermia, incidentally, is a fall in body temperature below about 35 degrees celsius - by this time, you'd be shivering uncontrollably.

But for today, we'll look at survival in the cold, and just what the risks are.

Some stories of cold exposure

In 1964, during the Four Inns Walking Competition in Derbyshire, England, tragedy struck when 3 hikers died as a result of cold conditions combined with poor preparation and planning for the cold. In this race (which is described by Pugh and later Noakes), competitors set out in temperatures between 0 and 4 degrees celsius, with wind speeds of about 45km/hour.

Seven hours into the event, the first reports of hikers in distress were received. In total, three hikers died as a result of the extreme cold and wind. In an analysis of these events, the following three characteristics were common to all three deaths:

• Inadequate clothing, which was not water-proof. As a result, when it began to rain, the water, combined with the cold and wind would have meant zero insulation for the hikers
• All the hikers had low body fat percentages. This was insufficient to make up for the loss of insulation by clothing once the clothes were wet
  
• The three hikers fatigued within a few hours of starting. As a result, they were walking very slowly, often collapsing, and hence unable to keep their rates of HEAT PRODUCTION high. The hikers who survived were those who finished faster.

These three points demonstrate the principles of exercise in the cold ON LAND - make sure you're dressed well, and make sure you are not forced to stop exercise or remain exposed for any longer than is necessary (unfortunately, this is not a choice we always have!)

In marathon running - evidence of hypothermia

The story above deals with hikers, exposed to snow, rain, wind and cold for days at a time. What about marathon runners? There is some evidence of hypothermia in marathon running. And perhaps surprisingly, it doesn't take temperatures below freezing to cause this. For example, in Scotland in 1982, in the Aberdeen Marathon, temperatures were about 12 degrees celsius, it was quite windy (25 to 30km/hour), but there was no rain, and yet 4 out of 59 runners finished with temperatures lower than 37 degrees! Similarly, in South Africa in 1985, during a 56km race, a temperature of 19 degrees combined with wind and rain was enough to see 8 runners taken to the medical tent with body temperatures below 37 degrees celsius!

Once again, in these cases, the likely cause is a combination of inadequate clothing, combined with low heat production as the athlete becomes fatigued. One of the body's responses to cooling is to shiver, and use more energy in an attempt to keep your temperature up. This is hardly conducive to performance and so the exercise intensity drops and body temperature tends to fall. Also, most of the time, athletes, particularly in South Africa, would expect reasonably warm conditions - they'd dress for these conditions, wearing little more than running shorts and a vest, completely inappropriate for wet, cool conditions, once the wind starts blowing. The same would apply to cycling, perhaps even more so, since the higher air speeds move heat away from the body more rapidly.

Having been in the medical tent at the last three Comrades Marathon events (90km race), I can also testify that towards the end of the day (around 4 or 5pm), when temperatures have fallen to the low teens (not cold, by any means), many runners report to the medical tent feeling very cold, shivering uncontrollably. And a big part of it is that they are fatigued, exhausted from the preceding 80km. They walk more, which causes heat production to fall. At the same time, they are underdressed, and then unable to do two jobs at one time - provide energy for exercise and for keeping the body warm. So the athlete often pays by cooling down and feeling very cold.

More recently - a high cost for winning a race

So we've seen that on land, the biggest danger is that you'll be caught underdressed and unable to keep exercising hard enough to keep your rate of heat production up. Provided you combat these two potential problems, your risk of hypothermia is actually relatively low. However, there is still a risk of frost-bite, demonstrated as recently as this past weekend by the case of one Andrew Wells. Wells won the Frozen Otter Ultra Trek, a 64-mile trek on what is called the Ice Age Trail in the Northern Kettle Moraine State Forest.

Wells won the race not because he finished the 64 miles first, but because he was the only competitor to actually reach the fifth check-point of the race. Only two competitors reached half-way! That's how severe conditions were - it was nearly 15 degrees below freezing at times!

But Wells clearly kept warm enough to avoid the potential for hypothermia. But unfortunately, he was not as lucky when it came to frostbite. This quote comes from this news story on the race:

Wells said he never noticed the frostbite set in. "My feet were obviously frozen, so I couldn't feel them," he said. "And it was too cold to take my shoes off to check my feet. On my hands, I had mittens on, and just to take them off for 30 seconds, my hands got really cold, painful. I thought my toes were OK."

It turns out that Wells competed in only running shoes, one pair of wool socks and a pair of waterproof socks! He'll now have two toes amputated! This story demonstrates that the danger of hypothermia may be lower, but frost-bite is a real possibility. Interestingly, none of the other competitors had this problem, because most, it is reported, bailed from the race when they'd hd enough. Wells, on the other hand, pushed past the initial pain until numbness set it. So it certainly is possible to voluntarily exercise into health problems, but for most, the sensation determines the safe limit.

But the record belongs to...

However, all these stories pale into insignificance when compared to the record for LOWEST SURVIVED body temperature. This report, published in Lancet in 2000, reports the remarkable story of a skiier, who holds the distinction of record cold-survivor:

“A twenty-nine year old woman fell while skiing (18h20), and was trapped and partially submerged under a waterfall. After 7 min, emergency rescue was summoned and, after 40 min struggling in the ice water, she stopped moving. The rescue team arrived (19h39), commenced cardiopulmonary resuscitation, and transported her to Hospital…Her Tc, 14.4oC at the start of rewarming, dropped to 13.7oC (afterdrop), and then returned to near normal after 3h. She recovered to normal function…”

Remarkable survival, but I'm sure you can appreciate, a one in a million story, and most are not nearly so fortunate (she did have numerous complications requring many years of rehabilitation afterwards).

So these stories and situations are obviously what we all wish to avoid! And in our next post in this series, we'll look at what happens to the body when it's suddenly exposed to a very cold environment - we'll look specifically at water immersion.

So join us then, and in the meantime, if you're in the Northern hemisphere, remember, it's all in the clothing!

Ross

Apologies for the absence

Travails of travel, and my own exposure to the cold

Apologies for such a long absence - it must be the longest time between posts since we began The Science of Sport last April. But there is good reason - I (Ross) have been trekking across the continents to visit first Europe and the USA. I'm actually in Chicago right now, visiting Jonathan, as I write this. I'll be in Boulder this weekend, for five days, and then Phoenix and Las Vegas in the week after that. This I head off for a week in Egypt and then back to reality and work in SA. I'm visiting with Dirk Friel of Training Peaks while in Boulder - they've been regulars of the site, so that should be great! If any regular readers happen to be in those towns, and you feel like getting together for a run, a game of tennis, a ride, whatever, send us a comment to this post and I'll get in touch - it'll be great to meet up!

So the "holiday" has been mostly to blame for the lack of posting - again, apologies for that. The power cord to my laptop also chose the most inopportune time to die, and the result is that I've not even been able to post while sitting waiting for flights at the airport (and the wait is long, especially flying on South African Airways, who managed to botch a flight by an incredible 14 hours, and then turn an 11 hour flight into a 14-hour one to boot).

Anyway, back online now, and hopefully not going to disappear for weeks at a time in the future, though please pardon the less frequent posting for the next month or so.

The series on the cold - it's coming, eventually...

A while back, we mentioned that we'd be doing our latest series on exercise in the cold. And we haven't forgotten! But first the Pistorius story and then this trip has interrupted our "flow" a little.

But now that I'm in Chicago (and soon Colorado), I guess one benefit is that I get to experience first-hand the implications of exercise in the cold! It was about 15 degrees below freezing when I landed (the doors on the luggage hold of the plane froze shut), and it's been about as cold ever since. Coming straight out of a South African summer, it's been a chilling experience! I went for a run the other day, and my cryogenically frozen lungs have been defrosting ever since!

So we'll get into the series on the cold. It's a difficult one to conceptualize and to apply practically to sports like running and cycling. Because at the risk of over-simplifying things enormously, when you run and cycle in the cold, the biggest problem is simply sensation-related. That is, overcoming the problem is mostly a function of choosing the appropriate clothing! That's of course an oversimplification, and we'll go into a little more detail than that, but the truth is that it's only when you get INTO THE WATER that cold physiology gets really interesting.

Now Jonathan and I both worked with the Polar swimmer, Lewis Pugh, first when he prepared for his first Arctic swim in 2005, and then Jonathan later that year on an expedition to the Antarctic. So it was from that experience that we dipped into cold water physiology. So a good deal of our posts on the cold will be on COLD-WATER exposure, but we'll also look at implications for running and cycling, as that's more our readership.

The difference between what you ARE and what you FEEL...

I also happened to catch the NFC Championship game the other night, from Lambeau Field in Green Bay. For those who don't know, they played the game at a temperature of -3 degrees FARENHEIT - that is a temperature of - 19 degrees celsius, folks! And it gets worse - with wind chill, they were reporting on-field temperatures of -31 degrees celsius! And it was interesting to see how the game dynamic changed as a result. I have no doubt that a good proportion of the 'basic' errors committed during the match were down to the cold.

As a teaser to the series on the cold, one of the most profound effects of cooling is that the conduction speed of nerve impulses and the force of muscle contraction are both reduced. This happens right away, long before the body temperature has dropped. So simply cooling the skin creates this effect - you don't actually have to BE cold to experience this - you just need to FEEL cold (and as we'll see in the series, there is a big difference between what YOU FEEL and WHAT YOU ARE!).

Anyway, a lot of balls were dropped, many passes just a meter off target, and much of that, I am sure, is down to the impairment of muscle contraction and nerve conduction by the cold. But that's what we'll be sinking our teeth into over the next little while, along with other, smaller stories that happen to come up.

So join us then, and again, apologies for the less frequent posting!

Ross

Haile Gebrselassie: 2nd fastest time ever

World marathon record eludes Gebrselassie in Dubai

The Standard Chartered Marathon in Dubai offered the richest payday in the history of the sport - $250,000 for the win and a bonus of $1 million dollars for breaking a 4-month old world record. And Haile Gebrselassie had his eye on both prizes as he lined up for his first marathon since claiming the world record with his 2:04:26 performance in Berlin last October.

However, it was not to be, and Gebrselassie missed out on the world record by 27 seconds, running a time of 2:04:53. His reward - the win in the second fastest time ever. The first man to run sub-2:05 twice. The two fastest marathon times in history, achieved in consecutive races in a 4 month period. The consolidation of his position as the fastest marathon runner ever. Yet, strangely, a sense of disappointment that is the result of just how good he is.

Where it went wrong - too fast, too soon and pacing problems

Haile Gebrselassie had talked up his chances of a world record in Dubai, and everyone else seemed to echo his sentiments. The talk from many circles leading up to the race was 2:03-something, with Gebrselassie himself talking of the 2:03 limit, both in the immediate aftermath of his Berlin World record and leading up to this race. But Gebrselassie is an entertainer and inspirational character for this reason - he's never been shy to talk up the chances of a world record, and 26 successful attempts suggests he is able to walk the talk.

However, in Dubai, a suicidal early pace put paid to any chances of a world record. Remember, at the start line, he needed to average fractionally faster than 2:57/km to crack the world record. His first 10km was run in 28:39 - that's a pace of 2:52/km, which projects a 2:01 finishing time!

For comparative purposes, when Gebrselassie broke the world record in Berlin, he covered the first 10km in 29:25, a full 46 seconds slower than in Friday's Dubai race. It's difficult to know just how the pacers managed to get it so badly wrong (5 secs/km is an enormous pacing error at that level) - you'd have thought that some feedback on the course after the first two kilometers would have seen the pace drop down. But this never happened, and the pace continued unabated.

We actually suspect that the feedback might have been purposefully ignored, and that Gebrselassie most likely asked for the pace to be maintained, perhaps feeling in great shape. Remember, no major challenges or threats were going to be coming from behind, and so Gebrselassie may have decided to "take the plunge" and see what happened off the back of this pace. It's difficult to know how else an experienced runner would get the pacing this far off.

Between 10 and 21km, Gebrselassie continued to grow the margin between himself and the world record pace. At halfway, Gebrselassie's time in Dubai was 61:27, projecting a 2:02:54. Remember, that when Geb ran the world record in Berlin, his SECOND HALF was covered in 61:57, and that was a remarkable performance. He now ran the first half a full 30 seconds faster, and it was perhaps inevitable that he was going to slow down in the second half.

That he did, and between 35km and 40km, the record slipped away. Eventually, a second half of 63:26 saw Gebrselassie finish in 2:04:53, a second inside Tergat's old record.

An indication of just how tough 2:03 will be

This race, then, is an indication of just how difficult a 2:03 will be for the marathon. After breaking the record in October, there was a lot of debate in the media about whether the 2:03 would be possible, particularly for Gebrselassie. We had this debate here at that time, and predicted that based on Gebrselassie's splits from the world record, this was very premature talk. Simply put, there just didn't seem to be margin to suggest that a 2:03 was on the cards.

That showed today, where the pace required for that time was simply too fast - a low 2:04 is perhaps possible, but the halfway split which projected 2:03 was too fast, by perhaps 45 seconds. And Dave Bedford's call that a 2:02 is possible in the next 6 years does really seem out of reach - that would require the athlete to run 30 seconds faster than Gebrselassie for his first half in Dubai, and repeat it all over again!

Looking ahead - Gebrselassie's next marathon - BEIJING

So ultimately, a disappointment, but only by the standards set by Gebrselassie. He cannot be unhappy with the performance, however. Consistency in marathon running is a valuable commodity, since the margins for error in the event are so small - training, race day conditions, pacing, and all other aspects of preparation have to be absolutely ideal to run a great time. And so to run two consecutive sub-2:05 times means that Geb has clearly mastered the preparation for the marathon, which will stands him in good stead for Beijing.

One training period too far?

On the other hand, two incredibly fast marathons in two starts within four months, and the prospect of another six months of preparation for Beijing (Gebrselassie is not running London and there are unlikely to be other marathons between now and the Olympics) lies ahead for Gebrselassie. Looking back on his last two years, this means that by August, Gebrselassie will be into month 24 of his quest for the perfect marathon - remember that he began the "quest" for the perfect marathon in October 2006, with his near miss on Tergat's world record. That was followed shortly after by an attempt in Fukuoka, then London, then Berlin, and now this race. And that does not include his races prior to Berlin 2006.

In effect, then, every marathon in the last two years has represented a hyped-up focal point in Gebrselassie's career and training cycle leading up to the race. Six marathons in 24 months (if we include Beijing), and every one a world record attempt...there has been little opportunity for downtime given this schedule, and the demand of both training and racing for these enormous performances might be a physiological warning signal. Will Beijing be one marathon too many? That's impossible to tell, though it would not be the first time a great athlete has stretched himself over one too many big training periods. It is yet another pointer towards a fascinating Beijing marathon.

Ross

Oscar Pistorius: The "missing" variables?

Pistorius to seek "independent" tests - the debate continues

On Monday this week, we did a double post, looking first at the report issued by the IAAF on the results of their testing of Oscar Pistorius, the "blade runner". This was followed by a post looking into the immediate response by Pistorius, where he declared that he would challenge any ban and ruling from the IAAF.

Well, Wednesday is as long as it took to hear more on that "challenge", though at this stage, the specific details are still very sketchy.

But in this news report, Pistorius was quoted as having said the following in an interview with Associated Press Television News:

"I was pretty surprised by the outcome...We have given the results to some university professors of biokinetics in the U.S. and they strongly believe I do not have an advantage," Pistorius said. "We are hoping to redo the tests at an independent level."

Pistorius was further reported as saying that the experts he'd consulted with had told him that the testing was not comprehensive enough, hence the need for more testing.

What might the IAAF have missed?

Now, this report is nothing especially new. But conspicuous by its absence is any detail on the testing, which has yet to emerge. That is perhaps understandable, as at this stage, there is no point in revealing everything.

But it is still enticing to debate just what these "missing tests" might be, and whether there might be any more to this (protracted) story.

The debate has gone on for some time now, which is why this concept of more testing is intriguing - there is either something everyone has missed, or this is a play to remain in the public eye as long as possible. Certainly, there is nothing that has been reported in the media, nothing that has been covered in this blog, and nothing else that I am aware of in the scientific literature that could possibly still be examined. I believe that the IAAF testing was in fact TOO broad and probably looked at too many variables. But that's not the main issue here. Rather, there are a couple of things things that Pistorius must account for in his "independent" testing.

We're back on the conflict of interests again

First things first though, it's hardly appropriate to call it "independent" testing! Regular readers of our blog will know that one of the biggest 'influencers' of scientific research is the conflict of interests that arises whenever a commercial company funds research on its own products. Think of the Gatorade Sports Science Institute doing research into sports drinks - they're hardly going to conclude that the benefits are insignificant. And here we have a case of an athlete/his team who are going to seek testing to find what exactly? That he has no advantage? It seems to us rather that Pistorius is seeking an alternative analysis in the hopes of the results being in his favour. It will be most interesting if this second analysis also shows he has an advantage. Then what? A third opinion?

That is not science, it's marketing and this whole scientific debate is in danger of degenerating into something of a protracted, drawn out affair, with farcical processes. It would seem that the only satisfactory conclusion will be when the science concludes there is no advantage and the IAAF allows Pistorius to run.

Two strikes so far - third time lucky

Going back to last year in July, when the story first broke, Pistorius was allowed to run in Rome and Sheffield, where the IAAF performed research on him during his races. Once the findings suggested some "unusual" pacing, Pistorius blasted the IAAF as "pathetic and incompetent" and accused them of spying on him. So that was strike 1, if you like.

Subsequently, the IAAF spent 50,000 Euros on a research study to establish the facts. When it was announced, Pistorius praised the opportunity and declared that the testing would clear up any doubt. But those results, which suggest a massive advantage, have similarly been dismissed as "incomplete" and inappropriate, despite the fact that Pistorius was given opportunity to choose representatives to oversee the testing to ensure its fairness. Strike 2, in effect.

So it would then seem that the only course of action that will satisfy Pistorius is when HIS OWN nominated scientists find no advantage, much as they suggested a 240% energy return.

The independent testing has already been done, and it found differences of 25% in energy consumption and never seen before energy return compared to the human limb. So to refer to further testing as "independent" is probably best forgotten - you KNOW that there's only one outcome possible from this "independent" testing, before it's even done. In fact, one statement from Ossur, who make the blades, would have us believe there "is no advantage". They swear there's no advantage, so it must be true...?

But, it 's still worth considering what possible variables might be considered - this is speculation of course, and we wait to hear exactly what it is. But given how this story has progressed, it seems prudent to anticipate what will happen - Pistorius might well have been the only one "surprised" by the IAAF result.

What variables still need to be considered?

All we can go on here is past stories and reports, because there has been a noticeable lack of real science originating the Pistorius camp since last July 2007. The only theory they did propose in support of Pistorius was the absolutely shocking, shameless scientific equivalent of "jock-sniffing," where they found scientists willing to say that the human tendon returns 240% of the energy it stores. This is at least three times higher than the reality, but it does give an indication as to how science can be made up when the need arises.

Are we destined to see more of the same now? I suspect so. I think that what will happen in the coming months is that scientific experts from the USA will be called upon to interpret results in a manner that supports the absence of an advantage. Quite how you erode a 25% advantage will be interesting to see...

The size of the differences - too large and too significant to be overturned

For the biggest challenge facing Pistorius is to overcome the sheer size of the difference - the IAAF found absolutely enormous differences. When we talk about elite athletes, 25% is a lifetime. In fact, if we took Kenenisa Bekele (who has a 10km PB of 26:17) and tested him in a laboratory to compare him to 5 other athletes who ran times of between 28 and 29 minutes for 10000m (this is a good two minutes slower than Bekele, bear in mind), I can assure you that we would find differences of no more than 5%.

The same goes for Jeremy Wariner - in a laboratory, I would be willing to bet that the difference between Wariner, the World's best 400m athlete, and an athlete who runs a 46 second time and can't even make the second round at the World Champs is not more than a few percentage points, if that. The fact of the matter is that in the laboratory, you simply struggle to find differences that are so huge between athletes who have huge gaps in their performance ability.

Yet here we have differences of 25 to 30%! That is astonishing, and even Prof Brueggemann admitted that he was taken aback by the margin. How many seconds does this equate to? That's difficult, if not impossible to say - but it's certainly not milliseconds.

So if Pistorius and the experts have some tests in mind, they have to find a disadvantage that outweighs this 25 to 30% advantage. Otherwise, the net conclusion must still be advantage.

So what might those tests be - lack of ankles, increased work for balance?

Turning now to what those tests might be, the only two things that have been mentioned in the media previously by the Pistorius camp (and their scientific team who would have us believe that the human ankle is capable of creating energy - is there not a million dollar reward for creating perpetual motion?) are the following:

1. Pistorius does not have an ankle, so to run at the same speed, his other muscles must work harder
2. Pistorius must work harder to keep his balance and so his overall energy cost would be higher.

Is it possible that these two things, neither of which Pistorius might believe are measured by the IAAF testing, are the "missing variables?" There was one other theory, which was put to us on this blog by a scientist in Canada, and this is that the limb moves around in the carbon fibre blade - that is, the "fit" is not ideal and so Pistorius would need extra energy because of the loss of energy through this inefficient attachment.

So those are the three possible arguments, as near as I can tell. But here's the catch...the IAAF have already measured all three, as implicit in their result.

In otherwords, when the IAAF measured how much energy Pistorius used during sprinting, they found that it was 25% LESS than other runners at the same speed. This energy use is measured in Pistorius, not in the limbs by themselves, and so it already includes:

1. The extra work his muscles might be doing to make up for no ankle
2. The extra work that he might have to do to stablize the body during sprinting
3. The loss of energy through the inefficient attachment

The point is, Pistorius is running using 25% less energy despite these differences - that's the advantage of the blades.

So, those three possibilities are out. Which leaves us with....? Any takers? If there are any experts out there who do have something to contribute to this one, we'd love to hear from you.

And then what of the Paralympic athletes?

The other group of people we would really love to hear from is the Paralympic community. Pistorius has openly declared that he is fighting out of obligation to the Paralympic community. Yet they have remained silent on the issue. We had a great couple of comments from one such athlete, Kara (USA Swimmer), and her views on the subject are very interesting - you can read them in the "Comments" section of this post. And I've seen some interviews where athletes have expressed lukewarm feelings, but other than this, no one has really asked - and a simple Google search reveals that.

What I suspect is happening though, is that Pistorius has consulted people who have expertise in prosthetics, but not in the physiology of performance. It must be emphasized that this specific case is very much about performance physiology. Sure, the prosthetics are important, but so unique is the situation that the answer will not come from a prosthetics textbook. The answer, I feel, came from Prof Brueggemann and a team of 10 scientists, who did EVERY POSSIBLE test and found an advantage that is probably comparable to the advantage in physiology that Jeremy Wariner enjoys overa typical high school or club athlete.

The debate continues...

Ross

Oscar Pistorius announcement: Banned

Two posts today:

1. The IAAF report on Oscar Pistorius is released, with the finding that Pistorius has a "clear mechanical advantage" over able-bodied athletes.
2. Discussion, insight and review into the history of this debate, as well consideration of Pistorius' intention of challenging the IAAF ruling (this post can be found further down the page)

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Oscar Pistorius banned by IAAF - carbon fibre blades offer "Clear mechanical advantages"

After two postponements, the IAAF have today released the report based on their testing of Paralympic athlete Oscar Pistorius. The details of the report, which we'll do our best to get hold of, are enough for the IAAF to prohibit Pistorius from competing in the able-bodied Olympic Games later this year.

You can find a copy of the IAAF press release here. If any more information or data emerges, we'll do our best to make it available. But briefly, our analysis of the IAAF results is found below. There is obviously a lot more to the theory behind these results and the discussion, but honestly, it's all been said before - about 6 months ago. So the results of this testing merely confirm what was being said back in June 2006. Therefore, we won't go into massive detail in this post, but rather redirect you to this post, where the scientific theories were evaluated.

1. Energy consumption: 25% lower with Cheetahs

The first important finding of the IAAF study is that during running at a given speed, Pistorius uses 25% less energy than the runners he was compared to.

Why is this significant?

It suggests that the Cheetahs are far more efficient than the human limb. In fact, that point was argued extensively last year, and the theory is that running on the Cheetahs will save energy investment. They reduce the demand for muscular work, and this in turn, enables Pistorius to run faster before potentially detrimental physiological changes occur and force him to slow down. In fact, this was EXACTLY what would be predicted.

Having said that, the magnitude of the difference is enormous. I had thought perhaps a 5 to 10% difference (which is still massive), but to have a 25% reduction is quite astonishing in terms of the advantage it would confer.

2. Energy return: Never seen before levels of energy return

Secondly, the research found that the carbon-fibre Cheetahs returned energy during running at levels never seen before in the human ankle. That is, the Cheetahs were able to store and release far more energy than a human leg ever has been measured to do. In fact, in a related finding, it is reported that the returned energy from the prosthetic blade is close to three times higher than with the human ankle joint in maximum sprinting.

Why is this signficant?

This is part of the mechanism for the first finding of lower energy use in Pistorius. In other words, Pistorius is investing less energy, and having to work less hard than able-bodied runners to sprint, because his legs are providing greater returns. So not only is he investing less energy, he is getting more out. Once again, the consequence of this is that he can run at the same speed with less energy, and hence is able to run faster than his physiology would allow him to.

3. Less vertical motion during running

The third key finding is that Pistorius, running with the Cheetahs, displayed a much lower vertical oscillation than the able-bodied runners during sprinting. Also, the vertical impact forces were lower in Pistorius compared to able-bodied runners.

Why is this important?

As with the first finding, the lower vertical movements means less energy is lost during landing and less used during the push-off phase of running. It has long been believed in the scientific literature that when you are running, a more economical runner will have a reduced vertical oscillation compared to an uneconomical runner. The Cheetahs provide this economy, and this contributes to improved performances.

4. Energy loss is much lower in the Cheetahs than the human leg

The fourth key finding is that the amount of energy lost during the stance phase of running was only 9.3% with the Cheetahs, but was 41.4% in the human ankle/leg. This difference, greater than 30%, is responsible for a large mechanical advantage compared to the human leg.

Why is this important?

Once again, it means that the physiological and metabolic work that is required of Pistorius is much lower than that of able-bodied runners, because he's losing far less energy. In order to run at the 400m speed, kinetic energy must be "created" through muscle contraction in all runners - the burden on the able-bodied runners is far higher, since they lose more energy. And, as seen in Finding Number 2, they also recover far less energy (three fold difference), adding up to a massive advantage for Pistorius - this is again part of the mechanism for the lower energy cost of running.

The sum of the findings

The sum of all these findings is that the Cheetahs contravene IAAF rule 144.2, which is that a technical device may not be used if it aids performance. As a result, Pistorius has been prohibited from using them, which ends (for now) his chances of competing in the able-bodied Olympics.

Pistorius has however already said he'll challenge the ruling and has come out in a hostile attack on the IAAF and researchers for leaked comments. In addition, he has suggested that they have not assessed enough variables to make their decision.

The problem with this is that even if they do test another variable or two where he does not have an advantage, he now has to overcome a 30% advantage regarding energy storage, and 25% advantage regarding energy use during sprinting.

The sheer size of these PHYSIOLOGICAL differences is staggering and one can only speculate as to what sort of performance advantage that gives him in a 400m race. 5 seconds? 10 seconds? It's very difficult to relate performance to physiology, because so many factors are integrated to produce a 45 second 400m race. But one thing that is for sure - we're not talking milliseconds here, it's a "considerable" advantage, to quote Prof Brueggemann.

But Pistorius has promised to challenge, and we discuss the history of the debate and Pistorius' possible challenge in a separate post, which you can read here.

We'll get more insight on these results as soon as we can!

Ross

Oscar Pistorius reaction: Challenge the ban

Pistorius to challenge ban - insight and overview of the debate so far

Earlier today, the IAAF released a press statement summarizing their findings on the testing of Oscar Pistorius. Based on the testing, Pistorius has been banned from competing, due to a "clear mechanical advantage".

We've analysed the results of the reports here, and below is a brief overview of the history of the debate, and the news that emerged on Friday that Pistorius will challenge the verdict.

Pistorius will fight the ban

In a statement issued on Friday, Pistorius declared that he would challenge any ban, pre-empting the IAAF verdict which was only announced today (though, again, it was a badly kept secret).

He blasted the testing procedure, the IAAF and in particular, the "premature and highly subjective statements" made by Professor Gert-Pieter Brueggemann. For the record, Brueggemann was reported in a German newspaper as saying that Pistorius "has considerable advantages over athletes without prosthetic limbs who were tested by us."

The world authority on running biomechanics and Pistorius

I'm not sure what the details of this "leak" were, though I know that the IAAF were disappointed at it as well. However, more to the point with regards to the current situation, is that you can hardly call the scientist who tested you "highly subjective", as Pistorius did. Yes, they were unfortunately premature, but to suggest they were subjective suggests that the science is perceived as a bit of a side-show, not carrying much weight. Of all the scientists on the planet, Brueggemann, a world leader in biomechanics of running, is now the best placed person to comment OBJECTIVELY on Pistorius's carbon-fibre blades.

However, one can hardly blame Pistorius for challenging, despite his statement from last year in July, when he said that he would accept the results from this particular testing bout. Apart from the obvious human interest aspect, and the emotion of the issue, there is the desire to keep the story alive. For Pistorius, the longer this controversy remains in the public eye, the better, because his entire strategy is public opinion, not science.

Indeed, Ossur, the company that makes the Cheetahs, have come out and said that there is no way the blades give him an advantage. Well, of course they say that - how much money and free exposure do they stand to gain if he can run? They could hardly admit at this stage that there is an advantage. Yet it's a statement with no evidence - it's only "true" because they say so...

The debate in the courts of public opinion

I've written before, but it's worth emphasizing, Pistorius and his team will have known since January 2005 that they needed to get science to support their Olympic aspirations. As soon as the curtain had fallen on the Paralympic Games of 2004, and Pistorius first mentioned his Olympic aspirations, the obvious requirement to get some kind of scientific support was identified - it was undeniable.

It was therefore clear from 2005 that any dreams of Olympic qualifying depended on getting scientific testing done. Yet three years passed, and not a shred of scientific evidence emerged. In fact, not even a shred of reasonable theoretical basis has been delivered, apart from continued claims that "the legs don't provide an advantage". This was always going to be a debate based on science, but only one side (IAAF) eventually spent money to bring that data to the table. Now that the data is on the table, we still have claims about "too few variables" with no proactive effort to bring science forward as well.

The evolution of the debate

Instead, what happened was that Pistorius got in touch with a "scientific expert" who made the absolutely absurd statement that a human leg could return 240% of the energy, three times more than the Cheetahs. The real figure, incidentally, is that the Cheetah returns 90%, the human leg between 30% and 70%. And this is not even the crux of the argument - the real issue is the physiological cost of storing the energy in the first place, not the return. And it's here where the Cheetahs cost little, whereas the human leg "invests" to get out - that's the key difference.

And so the "science" was performed and the entire focus on the campaign moved towards accusing the IAAF of discriminating without reasonable grounds to do so - public support tours in the USA, press statements about his discipline and work ethic, multimillion rand sponsorship deals and promotions - all the while, the evidence that needed discussion was overlooked.

The IAAF - a commendable effort

In response, the IAAF bent over forwards, backwards and sideways. First, Pistorius was tested in a race in Rome - the analysis of that race showed that Pistorius did indeed have a distinct advantage when it came to fatigue tolerance. By itself, that was interesting, but not definitive. However, you have to interpret that data in the context of the physiological theories and arguments that were made leading up to the race. Indeed, the entire basis for why the Cheetahs do give Pistorius an advantage is that his fatigue-resistance will be better than any other runners because of the carbon-fibre blades. The predction what would be made is that he'd run the 400m EXACTLY the way the IAAF found he did.

That finding alone should have been enough to ban the use of the Cheetahs. However, the IAAF then consented to the testing and the report we are now discussing. At a tidy cost of 50,000 Euros, the sport's governing body tested an athlete who could well have been asked to provide the data himself.

Too few variables tested? Or too many?

And now we have those findings. Yet still, the battle goes on. Pistorius has angrily said that the IAAF have not tested him sufficiently to make the decision. In his words:

"The data that has been collected from the testing considers too few of the variables that need to be examined to make a decision of this magnitude".

What is interesting about this is that BEFORE this testing was done, Pistorius was given opportunity to take his own group of advisors and experts with him, to oversee the process and make sure that the testing was done fairly. However, the result that has come back negatively has spurred him to consult other experts who now believe he was not given a fair run. This is much like the previous case of selective hearing where scientists refused to simply endorse the use of the limbs until Pistorius was able to find an expert to say that the Cheetahs were inferior to a human leg.

In considering this challenge, then, one has to ask "Which variables still need to be tested?". If you look at the range of variables that were tested by the researchers in Cologne, it is exhaustive. In fact, I would suggest that they actually tested TOO MANY things, many of which are actually unnecessary to the final decision. I wrote as much last year in December, suggesting that the risk of overkill (and hence false negatives) was great. So rather than having gone too low, I believe that the IAAF have tested too much.

Not that it matters much, because the results are so clear, so definitively suggestive of an advantage ("considerable", as Bruggemann wrote) that the issue should be laid to rest. To have found an advantage of 25% in terms of energy use, and 30% for mechanical advantages is absolutely massive - bigger than I even thought it would be, and it is difficult to see what possible test might overturn differences of this magnitude.

The perceptions within the Paralympic community

The one final interesting thing about all this is to speculate what the perceptions of Pistorius' fellow athletes are. Last year, around the time it was featured in the news, some polls revealed that more than half the paralympians DID NOT support Pistorius' efforts. Now, with this report being released to suggest the "considerable advantage", it adds further to the possibility that Pistorius has succeeded in pushing technology into the public eye as much as he has pushed the Paralympics into it.

I don't think there is anyone who does not find inspiration in the performances of Paralympic athletes. In this day of commercialization, I dare say that the Paralympics are closer to the Olympic ideal than the Olympics are! And so everyone watches these athletes with respect, admiration, even awe. But what is happening now is that Pistorius' crusade has confirmed the opinion that a runner on carbon fibre blades has as advantage over human legs...that was the reason given by one Paralympic athlete I saw interviewed. He did not want this issue to detract in any way from the performances of Paralympic athletes.

And of course, it doesn't detract from their achievements - they're still role models, more than the all-too-often drug using able bodied athletes. But now we know that the technology is a big part of the athlete. So next time a Paralympic athlete wins by 10 clear meters in a race, we'll all have knowledge that maybe, he had a better set of legs than his rivals. That is not good for the Paralympic movement.

And then finally, if I was a single-leg amputee competing against Pistorius in the Paralympics, I would now be lodging appeals against his participation there, because quite clearly, having two Cheetahs is better than having one. Therefore, the technology, and the findings of this IAAF report, would be usable to force the Paralympic movement to create a separate race for double-amputees, since they are benefitting much more from technology than single-leg amputees, who have a substantial balance problem to cope with during sprinting.

Opening Pandora's box

As was written last year in June, when this controversy hit the headlines: "Pandora's box has been opened". Back then, it applied to the possibility that the IAAF would allow the technology into the sport, which it has now prevented. However, Pandora's box has been opened all the same, except it concerns the role of technology in human performance. It will be interesting to see what continues to come out. But for now, it would seem that perhaps Pistorius is the last person to know...

Ross

Sir Edmund Hillary

Sir Edmund Hillary: 20 July 1919 - 11 January 2008

Many will have read, heard or seen news that Edmund Hillary, one half of the first pair to reach the summit of Mount Everest has died of a heart attack in Auckland, New Zealand. He was 88.

It was on May 29, 1953, that Edmund Hillary and Sherpa Tenzing Norgay, set out from a camp just above the South Col of Everest 7500m. By 11h30, they stood atop the highest mountain in the world. Tenzing left some chocolates as an offering and Hillary left a cross. A picture of Tenzing Norgay atop the summit (right) was the sole "memento" from the trip, since Norgay himself did not know how to use the camera! (self-timers absent back then...)

Hillary was famously reluctant to reveal whether it was he or Sherpa Tenzing who had actually reached the summit first (not that it mattered too much, in my opinion). Hillary would always say that it was a team effort, the attempt made in unison, and never disclosed whether it was he or Tenzing. The picture of Tenzing led many to suggest that Hillary was actually second. However, Tenzing himself later recounted in his book that Hillary was first by a few steps.

Breaking the barrier

Regardless of who took the lead on the final straight, through what is now known as the Hillary Step, the two men opened the doors for others to follow. In 1978, Reinhold Messner and Peter Habeler were the first to climb Mount Everest without supplemental oxygen, and in 1980, Messner became first to do the climb solo.

And just as we think of world records in sport as barriers that take as much mental effort as physical effort, so too the summit of Mount Everest was an "unbreakable" barrier. Reports from 1924 were that two British climbers, Mallory and Irvine, had reached the summit, but this was never substantiated, and Hillary and Norgay were in fact looking for evidence of their presence when they made their attempt - none was reported (Mallory's body was eventually discovered in 1999. Irvine's has yet to be found, and the debate goes on).

Instead, it is Edmund Hillary and Tenzing Norgay (who died in 1986), who are credited with breaking the barrier. Interestingly, the early part of the 1950's saw a race to smash two unbreakable barriers. One was Mount Everest, the other was the four-minute mile, and the world saw both eventually broken within a year of one another (the four-minute mile was run on May 6, 1954).

Also, we acknowledge that the field of exercise science is always moved forward by human performance at the extremes - think exercise in the heat, and the altitude Olympics of 1968. And no barrier was as challenging as Everest, at 8848m.

The really interesting thing about the Everest ascent is that it was
debated whether or not it was possible, even with oxygen, to summit the mountain. Physiologists at the time were not 100% sure that it was possible, and only later did a more complete physiological understanding emerge, including how changes in the earth's atmosphere as a result of its geoid shape made Everest "conquerable" during a specific window period each year. But it was Hillary and Tenzing who did a service for everyone, by showing the way to the top of the world, physiological "impossibility" or not.

For an excellent interview with Sir Edmund Hillary, with insights into the character of the man who led the way to the top of the world, check out this link. In it, Hillary reveals fascinating anecdotes from that expedition and what inspired his journey to eventual history.

But we'll leave off today, and this week, with a quote from Hillary during an interview. He was asked whether at any point during the final attempt on Everest, he felt that he and Tenzing were NOT going to make it.

"Never, at any stage, until we actually got up the rock step, was I confident that we were going to be successful. My feeling was that we would give it everything we had, but we had no surety that we were going to reach the top. In fact, I believe that if someone starts out on a challenging activity, completely confident that they're going to succeed, why bother starting? It's not much of a challenge".

Ross