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Tuesday, January 29, 2008

Exercise in the Cold: Part II

A physiological trip through cold water exposure

While we are all still thinking about the incredible video of Kayoko Fukushi's marathon finish, we thought we would carry on with our series on exercise in the cold. Most of us are still firmly in the depths of the northern-hemisphere winter, and so we hope you found Part I of this series relevant---it was meant to introduce some basics of heat loss and temperature regulation, and also look at some of extreme stories such as the runner who "won" an ultra-marathon by being the only one to complete the race in below-freezing temps. The price of victory? Losing two toes!

Water vs. air exposure

In tackling this series on exercise in the cold, we differentiate between cold AIR and cold WATER exposure - the key difference is that the heat LOSSES in water are so much greater than on land, that you're far less likely to develop any kind of hypothermia (low body temperature) on land. In fact, water conducts heat about 25 times better than air. So when water moves across your skin you will lose heat more quickly compared to air simply because of its physical properties.

As as we said in Part I, the key to managing exercise on land is simply through appropriate clothing. But the introduction of some water to the mix ('Just add water') makes the situation far more complex and challenging and that's what we'll tackle today!

Too much heat to cool down - why hypothermia is the least of your worries

Perhaps the first, and maybe the most surprising fact about cold water physiology, is that your body has too much heat to become hypothermic within about 30 minutes, no matter how cold the water is! In other words, it is not possible to get so cold that you're in danger unless you are in the water for more than about 30 minutes. The graph below shows this:

So from this graph, you can see that even at water temperatures of 0 degrees celsius, 30 minutes falls within the marginal zone, not the lethal zone. Many would probably survive for close to an hour - this is demonstrated by shipwreck victims, who have survived freezing water for this long.

The implication of this is that if someone is immersed in cold water, and dies, the cause of death is unlikely to be hypothermia unless that person has been exposed for a long time! Hypothermia is often wrongly blamed for death in people exposed to cold water - getting too cold is actually the least of your worries! We'll take a look at the main challenges a little later, but first, a key discussion about body composition and its effect on your ability in the cold.

Lessons from English Channel swimming

Perhaps the best forum in which to examine the physiology of cold-water swimming and immersion is English Channel swimming. The great British Exercise Physiologist Lawrence Griffiths Pugh performed a series studies in this area on the channel swimmer Jason Zirganos. Zirganos died from exposure to cold water while attempting to cross the Irish Channel, but his legacy was to leave behind a solid understanding of cold-water physiology.

The importance of body fat - 'fatter = warmer'!

The first important point about cold-water exposure is that body composition has a profound effect on core temperature during immersion. Pugh demonstrated this when he compared himself---the scrawny scientist type---to Zirganos, the chubby cold-water swimmer type. When just sitting in 16 C water the rectal temperature of both men fell, but after approximately 80 min Zirganos was sitting a full one degree higher than Pugh. The more dramatic difference was when swimming in the same water, though. Zirganos was able to maintain his temperature at around 38 C for nearly two hours while Pugh's temperature began to plummet after just 30 min until he exited the water after about 70 min, when his temperature was less than 34 C.

This early research from the 1950's pioneered this area of physiology, and today we have a substantial body of evidence that demonstrates both the effects of cold-water immersion and how we adapt to this stress.

The cold-shock response - the biggest challenge to survival in the cold

One of the first things you experience when submerging yourself in cold water is something called the "cold-shock response." This is characterized by an uncontrollable gasp for air, followed by a prolonged period of hyperventilation - more rapid breathing. In fact, this response is one of the most likely causes of death in most cold-water immersions such as when one falls out of a boat into icy water. It's not difficult to see that if the timing of that "gasp" is slightly wrong, you'll take in a huge lungful of air, and one or two gasps while underwater is all it takes to drown.

The other big 'killer' is a heart attack, which can result when the temperature of the blood returning to the heart is suddenly cooled - this can affect the electrical conduction within the heart, causing fibrillation. So it is these two possibilities - drowning and cardiac arrest that are most likely the cause of death. However, as we said, most times, people blame hypothermia for death, when in fact the body temperature does not need to fall for an unlucky 'swimmer' to perish in the cold.

Swimming in the cold - a problem of breathing and muscle weakness

Once you've overcome that problem, however, the next thing to worry about is swimming. And again, the hyperventilation that happens in the cold has a profound effect on the ability to swim in an efficient manner. The graph below, from a paper published by Eglin and Tipton in 2005 (EJAP) shows the breathing response of a swimmer exposed to cold water. It shows the BREATHING RATE in breaths per minute against time in a person who stands in a cold shower at 10 C.

So the rate of breathing goes up from about 16 breaths per minute to 75 breaths per minute, within the first 20 seconds. It then stays up at 40 breaths per minute for the next few minutes. It is not difficult to see how that would affect your ability to swim, because your stroke rate would have to change substantially to allow you just to breathe!

Next problem - the "DiCaprio" problem - a cold muscle, and cold skin, equal a weak muscle

The next problem is equally significant - when the muscle and the skin are cooled, the muscle becomes weaker! So the cold water on the skin will make a powerful swimmer incapable of swimming, simply because his skin is cooled. There is evidence from studies that shows that the ability of the muscle to produce force is as much as 25% lower immediately after exposure to water at 10 degrees celsius - this would only drop in even colder water. Then we add to that the fact that as you get cold, your body's natural response is to shiver. But when you shiver, your co-ordination is affected, making it even more difficult to swim!

This obviously has profound implications on ability to swim. And for all those who watched in despair as the character played by Leonardo DiCaprio could not swim to safety in the movie Titanic, you now have a physiological explanation - he simply could not swim, because his skin and muscles were too cold to contract normally! (Far be it for us to suggest that Hollywood portrayed that accurately!). The principle remains, however - a good swimmer in warm water will be an average swimmer in the cold. And a weak swimmer in the warm...well, that's a recipe for trouble.

The good news - adapting the cold shock response

So that is the bad news. . .but the good news is that humans are adaptable organisms, and just like we make adaptations to things like marathon training, we also make adaptations to stressors such as cold-water immersion. The data show that exposures to cold water as short as three minutes in a 10 C shower will attenuate the cold-shock response by as much as 20-30%. In the graph below, you can see the same data we showed above (Eglin and Tipton, 2005, EJAP), but this time, we've added in a comparison with the breathing rate AFTER six 3-minute long exposures to the cold water.

So you can see that only six exposures is enough to reduce the cold shock response by 20%. If you have even longer exposures, you can bring it down by 50%. That is obviously a significant reduction, and the implication is that swimming will be far easier if you are simply adapted to the cold.

The second important adaptation has to do with blood flow and heat loss. When at rest your muscle tissue actually acts as in insulator. This changes when you exercise because now you are pumping lots of blood to the working muscles, and it is the blood that transports heat around the body. Therefore when you start to swim in cold water you send more blood to the muscles, and all this does is increase your heat losses as now the blood----and the heat it contains----it close to the surface of the body and the cold-water. Since water conducts heat very well, the heat from your body readily moves to the water. . .and the consequence of this is a decrease in core temperature even though you are producing some heat with your muscle contractions.

Decreases in sh-sh-sh-shivering

Another big change that occurs with repeated cold-water exposures is that we lower our "shivering threshold," or the temperature at which we begin to shiver. The bonus of with shivering is that we produce heat as our muscles are contracting, although involuntarily. The bad news is that when trying to perform a complex movement such as swimming (or any dynamic activity), shivering can really foul things up. So we adapt by lowering the temperature at which we begin to shiver, and the result is that you can swim for longer before being hampered by shaking limbs and uncontrolled movements.

Evidence for non-shivering thermogenesis?

Finally, there is evidence that humans actually increase their core temperature either acutely or chronically in response to repeated cold-water exposures. The net effect of this response is that they can then remain in a cold environment for much longer before suffering any detrimental effects of the exposure, such as decreased nerve conduction velocity and then shivering (and a loss of coordination as a result of that shivering). Simply put, they have more heat in their bodies, and together with the other adaptations we mentioned above it means they reach a critically low temperature much later than someone who is not adapted to the cold.

So the take-home message here is that cold-water exposure is just like any other "stressor" or training stimulus. Our physiological response to these stimuli is to make adaptations that allow us to cope better with the , which in this case is cold-water immersion.

That wraps up Part II of this series, but stay tuned for Part III, when we will examine how the cold actually affects exercise performance!

Monday, January 28, 2008

Amazing marathon video

Kayoko Fukushi's debut - an amazing video of what happens when the marathon goes wrong

In our most recent post, we looked at some really interesting stories from the indoor athletics and tennis worlds.

But here's one that I felt should be added to this, and it includes a video which I found through the Let's Run website (great source of news).

The story, and the video, come from the Osaka Marathon over the past weekend. The full story of the race can be read here.

But the real story, from our point of view, anyway, was that of a Japanese runner, Kayoko Fukushi, making her debut in the marathon event.

Fukushi is Japan's national record holder over 3000m, 5000m and the half-marathon. Considering how many brilliant female athletes Japan has produced in the marathon, when one of their runners with such speed over the shorter distances steps up to the marathon, it is bound to cause a stir.

And so, at the Osaka Marathon, Fukushi lined up for her first marathon knowing that no Japanese woman had ever run faster than her over the half-marathon - a great source of confidence, no doubt.

But too fast too soon, and the price is paid

Perhaps a little too much confidence, in hindsight, because Fukushi set out at a pace of sub-2:20, leaving the entire field behind from the very first kilometer! According to reports, she ran about 3:20/km for the first 25km - just about on pace for 2:20. But by 32km, she had slowed substantially, run 3:42 for that kilometer. The rest of the field caught and passed her at about the 35km mark - she lost a lead of about 4 minutes within about 5 km! So the wheels had really come off.

Just how much did they come off? Well, take a look at this video (available also on YouTube), and you'll see her final kilometer, complete with frantic and excitable Japanese commentary, and a very enthusiastic crowd - it's quite an entertaining package and a courageous run, which we describe a little more below. The video is just under four minutes long.

Fukushi enters the stadium, falls flat on her face, stands up and soldiers bravely on. I timed her final 300m at 2 minutes and 21 seconds - a pace of 7:50/km! That includes two falls in the final 200m.

For more insight into this pacing strategy, the graph below shows the pace per 5km interval during her race. The blue line represents her pace (in min/km), and the maroon blocks are added to give an indication of the pace - they project a 10km time based on each 5km interval.

What is interesting as an observation is that she's not showing any mental symptoms like confusion (though she is smiling, which some would possibly say is a mental sign considering her physical state!). One of the main symptoms of hypoglycemia (running out of glycogen and hence your blood sugar levels fall) is deliriousness and confusion. Fukushi is running in a straight line (albeit slowly), at least. It's quite apparent that her physiology has basically shut down - she could not pick up the pace even if she wanted to. It would be really interesting to speculate just what percentage of her total muscle she's actually using. Is she using ALL the muscle? It hardly seems like. Rather, it looks as though something has put a brake on her running speed. This "central fatigue", characterised by poor co-ordination (she falls over repeatedly) and often, confusion (not apparent here) was recognised by scientists as a key indication that the fatigue was NOT simply in the muscles, but also in the brain.

It's also an illustration of just how badly things can go wrong if the early pace is too ambitious. Having reached half-way in 1:10.32, Fukushi covered the second half in 1:30.32! That's still a pretty respectable half-marathon time for many people, no doubt! It's all relative of course...

But then Fukushi's final 7.2km took her 40:25 (pace of 5:37/km), and her final 2.2 km was run at an average of 7:06/km, and includes that section from the video above! A courageous run by Fukushi, no doubt. One really interesting thing to debate is whether this is an "intelligent" act to continue. Just how much do the final 10km take out of her? Is there a chance that this effort will affect her future marathon running performances? Of course, it's just as easy to argue that she'll be stronger for it, and back for that 2:20 some day! Again, time will tell...

The moral of the story - patience, aim rather run a negative split, especially in your first marathon, and remember, you might pay heavily for a fast early pace!


Sports news - athletics and tennis

Signals of intent for the athletics season and a Grand Slam without Federer down under

Just a quick filler news article today, to comment on some very interesting sports performances from the past weekend. First, we look at some results from the distance races at the Reebok Indoor Athletics meeting from Boston - Ethiopian women in fine form and Craig Mottram signalling his intent for 2008.

Then we look briefly at the Men's final of the first Grand Slam of 2008, the Australian Open. As from tomorrow, we'll resume our series on Exercise in the cold.

Craig Mottram - sign of things to come?

Last year, heading into Osaka, we (and others) picked Craig Mottram's battle with the East Africans in the 5000m final as one of the possible highlights of the Championships. How wrong we were! Mottram never featured, eventually finishing 13th out of 14 runners, in what was the slowest 5000m race in the history of the IAAF World Champs. So having begun the season with great promise, Mottram failed on the biggest occasion. In the aftermath, it emerged that Mottram had been struggling with a hamstring injury, which curtailed his training leading up to the race.

Well, 2008 has begun much the same was as 2007 did - Mottram looking mighty impressive. In Boston, he ran the fastest time ever on American soil for an indoor 3000m - 7:34.50. He won the race going away, with a final 400m of 59 seconds. The time is only 2 seconds slower than Mottram's best ever OUTDOOR 3000m performance, and given that indoors, the time is expected to be 3 or more seconds slower, Mottram is clearly in great shape.

So what will be interesting to see in the next few months is whether he is able to remain injury free and whether he can sustain the level of performance all the way through to August. In terms of the injury, Mottram has said that he's not travelling full-time with a physio, specifically to work on the risk of injury.

In terms of performance, things might be a little trickier. With six months to go until Beijing, Mottram will need to maintain his current form through the indoor season, and then on the tracks of Europe, which will be a tough task. He's clearly got great speed right now - to have speed sufficient for a PB at a shorter distance like 3000m indicates that at some stage in the next six months, he'll have to pull back and reassess before sharpening again for Beijing - a tricky task. It might require very frugal racing in Europe, perhaps even none until about July. Mottram enjoys racing though, and so to maintain good speed all the way to August will be very tough. But hopefully he's got the timing right and will be in his best shape to mix it with the Africans come Beijing.

The Ethiopian women - dominant distance running performances

Meseret Defar and Turinesh Dibaba are only 24 and 22 years old, respectively. But they are well on the way to being the best middle and long distance athletes in history. Dibaba has four world track and four World Cross Country titles, and Defar was the Women's World Athlete of the Year in 2007, is an Olympic and World Champion, and makes a habit of breaking world records by seconds.

And this past weekend, Defar added another to her collection. Admittedly, it was a soft record - the women's 2 mile record. The old time was held by Regina Jacobs, at 9:23. Defar cleaved 13 seconds off it with her winning time of 9:10.50 - that's how soft it was! But the performance was still remarkable. The halfway point was reached in 4:38.4, which means the second mile was covered in 4:32! This suggests there is more to come, for a negative split this large is not optimal in this length of event. Not that Defar will get the opportunity soon - the 2 mile is too rarely run. But that kind of sustained speed over the second half suggests that a 3000m time very close to 8:20 later on this year, and her 5000m PB of 14:16 (the World Record) may also be under threat this year.

Unfortunately for us, it does not look as though the race with Turinesh Dibaba will happen any time soon. In Boston, we had the bizarre scenario where Defar ran 2-Miles and Dibaba ran the 3000m - basically, the same race. So it does provide a nice comparison, but would have been far more exciting to see them race head to head. That was denied to us last year in Osaka, after Dibaba withdrew from the 5000m after winning the 10000m title. And it seems unlikely that they will race again in Beijing, since Dibaba will surely focus on the 10000m event, and with the heat, it's unlikely she'll have the appetite for two 5000m races after.

In any event, Dibaba was an impressive, not spectacular winner of the 3000m race. Her time was 8:33.37. Quite a nice comparison is possible by looking at the time taken to cover the second half of the race - Dibaba reached 1 mile in 4:36.1, which means the final 1400m was covered in 3:57.2 (give or take a few meters). Defar's final mile of 4:32 equates to a 1400m pace of 3:56.7. So they are seemingly as inseparable as ever.

Of course, this comparison is somewhat shaky, and that's why the best solution would be to have them race one another. Unfortunately for the sport, this kind of situation often develops, where two high-profile athletes avoid one another for all but one or two races per year, if that. We had Powell vs. Gay (on, off, on and off again), and numerous others in the past. One can't blame the athletes for not wanting to race unless the right "carrot" is offered, but it certainly would give the sport a boost to have a great head-to-head contest for meeting promoters to hype up and promote.

Tennis action - new faces and new prospects

Moving onto tennis, and exciting times for the men's game. For the last four years, Roger Federer has so dominated the tennis world that everyone else in the Grand Slams was vying for the title of runner-up. With the exception, that is, of the French Open, where they were all hoping for a semi-final, right before Rafael Nadal disposed of them on the red clay!

And a month ago, we looked into our crystal ball and predicted more great Federer-Nadal contests. Well, the year's first Grand Slam is over, and amazingly, neither of these two even made the final, let alone against one another!

Instead, it was Novak Djokovic and Jo-Wilfried Tsonga who fought out an absorbing, if error ridden contest. In the end, Djokovic won in four sets, and claimed his first Grand Slam title. That after disposing of Federer in the semi-final. Tsonga, for his part, destroyed Nadal and if he can keep up his level of play, then 2008 promises at least four awesome performers, and that does not include a number of other prospects.

On the note of Djokovic, I was a big fan of his before this tournament, but what I have seen in the final week has only undermined that opinion. Djokovic comes across as petulant, supported by his family of four cheering him on with T-shirts emblazaned with letters spelling out N-O-L-E, which I'm told is his nickname.

But in yesterday's final, and in the match against Federer as well at times during previous games, Djokovic displays a petulant arrogance, even going so far as to shout and gesture aggressively towards fans. At one point during the final, someone in the crowd shouted "Stop" when Djokovic bounced the ball about 15 times before serving (Djokovic has this very annoying ball bounce routine, which has seen opponents complain to umpires, including in the final). In response, Djokovic angrily told the umpire to ask for quite (still acceptable). And then on winning the subsequent point, Djokovic first gestured aggressively to his family, and then turned specifically in the direction of the unruly fan and gave a very angry fist-pump, shouting something at him. It was a taunt more worthy of a drunken soccer fan, not a soon-to-be Grand Slam champion.

This kind of behaviour leaves a bad taste in the mouth, and it was not the first time. On many occasions, on winning a competitive point, Djokovic pumps his fist for the fans' benefit, posturing and preening, almost expecting their adulation. Unfortunately, in this final, he didn't get it - instead, Tsonga, who is all heart and spirit, was the fans' favourite. And whether this unsettled Djokovic, I don't know. But it seems quite clear that he has an attitude of disrespect towards the fan - yes, they are wrong to shout out as he's about to serve, but a great champion recognizes that the bad must be taken along with the good, and is gracious and humble enough to roll with these 'blows'. Instead, Djokovic shouts at fans to 'shut up', gestures angrily towards those who don't support him, and postures like a prize-fighter or WWE wrestler waiting for the respect and admiration.

Perhaps he can take a lesson from the man he beat in the semi-final, for Roger Federer has dominated with humility. Djokovic, on the other hand, is a new kid on the block, and has displayed little of the respect that Federer clearly has.

And sadly, it would be wishful thinking to suggest that Djokovic's support group and family will advise him in this regard, for it would seem that they encourage it. I have often seen people wearing T-shirts with slogans or letters that spell out the name of their favourite player. Usually it's the fans. But when the family of the player resort to that, I have to wonder. At one point early in the tournament, one of the four family members (it's him father, mother and two brothers) failed to stand up and cheer - the result was that their shirts spelled N-O- -E, rather than the intended N-O-L-E. In response, his mother turned and gestured rather angrily to her son to stand up, as he clearly wasn't doing his bit. Well, that seems somewhat unhealthy to me.

And in a world of tennis, where the parents of the players often court controversy and negative press more than the players (think of Pierce, Sharapov and Dokic), I'd prefer to see Djokovic just play tennis, rather than perpetuate this rather perverse affinity to a family that is only spurring on a WWE wrestling attitude on court. If any sports psychologists are reading this, please do weigh in and give your take on this behaviour that seems especially typical of tennis players...

Nevertheless, it's great for the game that Djokovic, and hopefully Tsonga, are so competitive, beating Federer and Nadal. It makes for a fascinating 2008, and a mockery of our crystal ball!

The week ahead

So that's it for the Weekend Sports wrap. This coming week, we'll get the series on Exercise in the cold moving. So do join us then!


Thursday, January 24, 2008

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!


Wednesday, January 23, 2008

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!


Sunday, January 20, 2008

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.


Wednesday, January 16, 2008

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...


Monday, January 14, 2008

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)
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!


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...


Friday, January 11, 2008

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".