Sport shorts: Ironman WR? Zabriskie's "vegan" diet?

Sport shorts:  Zabriskie's "vegan" diet and the Ironman World record

Two sport shorts for you today, because these topics both featured on our Facebook page and Twitter feed and generated a lot of chat, so they're worthy of putting out here as well.

Zabriskie's diet and the energy challenge of the Tour de France

First, the Wall Street Journal ran this piece on American cyclist David Zabriskie who is taking part in the Tour de France on what is mostly a vegan diet.  There's the fine print (or the asterisk in the headline) that says that he is allowing himself salmon for its nutritional value, but mostly, he's going with the non-meat options.

I did a link to this on our Facebook site and up jumped a great discussion (another reason to "like" our Facebook page - some good spillover stuff over there!), some 32 posts deep on the article and the diet, so I thought I'd bring it over here as well!

The energy demand of the Tour

The Tour is obviously a massive energy challenge - 5 to 6 hour days in the mountains are extremely energy costly.  Jonathan did this post a couple years back, describing the approximately 6,000 kCal per day energy requirements for a cyclist.  And that's just the average - the high mountain stages reach the 8000 kCal mark.

The challenge for a Tour rider is that they have to replace huge amounts of energy in a relatively short space of time - some is taken in on the ride, then the rest must be squeezed into a relatively narrow window after exercise, before sleep.  Strenuous training also has an "anorexic" effect in that it kills the appetite, and so generally, whatever energy deficit is there after cycling must be replaced in a space of maybe 5 to 6 hours.  That would equate to around 700 kCal per hour.

And so Tour riders are not just great cyclists, they have to be great eaters!  A study by Klaas Westerterp looked at Tour de France energy balance and found that the average energy cost of a day in the Tour was 6,100 kCal, and the riders managed to replace about 6,000 kCal per day over the 3-weeks.  In other words, they almost matched energy use.  Over the course of the Tour, a rider will lose some weight, and as I mentioned in yesterday's post, their hormone function does change for the worse over the three weeks of the race (cortisol up, testosterone down, for example).  So getting energy balance as close to optimum is of course vital.

The "vegan diet" and energy/nutrient intake

In terms of the Zabriskie "vegan + salmon diet", the question is HOW did the riders manage to almost on top of their energy use per day?  And the first significant point is that cyclists actually ingest huge amounts of energy DURING cycling.  It was found that 49% of the daily energy intake was achieved during the day's stage.  That's almost 3000 kCal on the bike, and it's achieved with the intake of 94 grams of carbohydrates per hour during racing (which made up 70% of the energy intake on a stage, so the riders do eat foods and get energy from fat and, to a lesser extent, proteins).

This means that much less has to be replaced after the stage, but highlights the importance of eating on the ride - if you don't, then you leave a significant 'mountain' to climb after the day's racing.

In the course of a 24-hour day, the energy came from the following sources: 15% from proteins, 62% from carbohydrates and 23% from fat.  For Zabriskie then, or anyone who wants to eliminate meat from the diet, the primary issue is whether it's still possible to get the energy intake right, and also to get the right levels of protein in.  There's some evidence that protein ingestion aids recovery, so while it may be  small as an overall percentage of energy intake, it may play a vital role in getting through the Tour.

Managing fuel for optimal performance

Now, I don't know enough about Zabriskie's diet to comment on its specifics. Also, I'm wary of going into that area given that I'm not a dietician and shouldn't claim to know specifics anyway - in this country, dieticians study for five years and specialize in the area for two, so I'm no more likely to get specifics right than they are details of physiology!  And in all my interaction with any athletes, my interest has been more the practical management of diet for elite performance, not saying "eat X not Y", or "add A, B and C to your diet".

However, I will say this.  A vegan diet does present challenges to meeting the energy and nutrient requirements of a Tour, because animal products make protein and fat ingestion easier, and are more energy dense.  But, a vegan-like diet does not make them impossible, for three reasons.  First, there are many ways to get nutrients in, it's sometimes a matter of getting creative (which, for a professional athlete on the road, can be very, very difficult).

The second reason is that the evidence from Westerterp suggests that half the energy replacement happens during the day's riding, and is mostly in the form of carbohydrates.  That would not affect Zabriskie.  So in reality, his challenge is to replace another 3,000 kCal, not the full 6,000 kCal per day.

The role of awareness and proactive diet management

The third reason that any diet can be effective, in my experience, is that awareness of nutrition is often a crucial factor that enables effective nutrition.  That is, simply being made more aware of diet improves diet in those individuals who want to improve!  This is why dieticians are often so interested in educating their clients about their food choices, and why tracking daily food intake helps.  There are studies, for example, showing that keeping a food diary assists weight loss without any other intervention - awareness leads to effectiveness.

And so my interpretation of the success of vegan or vegan-like diets (Zabriskie is one. Scott Jurek, I'm told, is another) is that often, they may be effective because the person going onto the diet is consciously aware that there are some practical limitations that must be overcome, and this awareness, combined with the more methodical approach to diet, helps the athlete eat better than they might have done before.

In other words, a diet that may be sup-optimal in concept can be more effective than an optimal diet, because the athlete is more invested, more aware, more careful.

The diet debate - a never-ending range of possibilities

There's going to be debate about whether a vegan diet is optimal or not.  Whether meat is better than vegan.  I could play devil's advocate, and bring up the concept of a paleo-diet, for example, which is the very opposite extreme that says that high protein is the way to go, that our bodies "evolved" for that diet and that our reliance on carbohydrates is sub-optimal and unnecessary.  This is even being applied to endurance exercise, and while I don't agree with it for exercise, there are cases and some compelling reasons why it can't be dismissed out of hand.  Then there are those who will argue for high carbohydrate.  And those who argue for everything in between - as I pointed out on Facebook, the diet world is full of new ideas, fads and revolutions, and the sciences are only really just scratching the surface.

The bottom line is that a Tour de France rider must replace the energy, and the nutrient (both macro and micro) composition of the diet must be carefully managed.  I think that a vegan-like diet is possible, but may introduce some challenges.  However, those can be overcome (in the case of Zabriskie, by adding salmon, among other things!), and in the end, provided one is sensible and balanced in the diet, performance can be optimized regardless of the global view of diet.

That is, don't argue "vegan" vs "meat", rather take a systematic view of everything in it, and that might reveal that barring the very far extremes (the zero carb diet, for example), the body is good enough to go on a range of different fuels!

The Ironman World best performance - 7:45:28

Then the second snippet for today is an Ironman World Record in Austria, and the hint of controversy that it has generated.

Yesterday, Belgium's Marino Vanhoenacker set the fastest time ever recorded in an IronMan event, when he produced an extra-ordinary 7:45.28 performance.  It came thanks to a 46:49 swim, a 4:15:24 bike leg (that's for 180km, for the non-Ironman followers) and a marathon time of 2:39:24.

Absolutely extra-ordinary times, particularly the run off a super fast bike leg, and it was enough to break the old world record (held by fellow Belgian Luc van Lierde) by 4:29.

Then this morning, I woke to suggestions that maybe the course was short.  It was being said that the bike leg was around 4km short, and the run somewhere between 0.5km and 1km short.  Those distances are probably worth a combined 6 to 8 minutes, and so if true, it would account for the times.

However, I've spent the last half-hour trawling to confirm this, but so far, nothing.  Even the official Ironman Website carries Vanhoenacker's picture and a headline of the World Best time, and so it would seem that the rumors are unsubstantiated.

Most of them come off chat forums, from people who have participated in the event and measured it with their own Garmins, or who have mapped the course on mapping programmes.  I guess the question is whether the accuracy of those exceeds that of the official course measurements.  This is something that has seemed to come up every time I've written about Ironman events - last time, it was in relation to Chrissie Wellington's performances.  There seems some real dissent about courses, some that are rumoured to be more lax than others with measurement.

But given that this race is part of the Iron Man series, and given that it is in its 13th year, I'd be very surprised if it was short and that they still carried news of it on the official website.  Then again, stranger things have happened, but I think for now, we have to recognize that the World Best time stands, until the official IronMan organization suggest otherwise.

So Marino Vanhoenacker is the current Ironman World record holder (insofar as we have WR for different courses - world's best is the more accurate term, but that's picking holes).  A 2:39 marathon off a 4:15 bike is an exceptional performance, for sure.

The Tour continues

Tour de France coverage continues, a video soon on the power output numbers from the Tour

Ross

Chrissie Wellington on the charge and other marathon stats

Chrissie Wellington charges in SA Ironman and some other interesting marathon stats

I know I'm in the process of building a series on Talent Development and specialization, but today is a frantically full work day, and there are some really interesting sports stories from around the world, so I thought I would deviate to a (not totally) unrelated topic and look at two of them in a quicker post.

First, Chrissie Wellington was at it again yesterday, this time in Ironman South Africa.  She won the race in Port Elizabeth in a new women's record for Ironman events, an extra-ordinary 8:33.56.  That broke her own Ironman record of 8:36.13, set last year in Arizona.  That time was good enough for eight overall, and perhaps most remarkably, her marathon split of 2:52.54 was the fastest of the day, men or women (just a note, her fastest ever time is from Roth, an 8:19.13, but a number of people have suggested that this is a short course.  Others say it's not - I can't verify who is right on this one!  The men's time there is also super quick, so whether it's short or just fast, comparisons of Roth to other events seem a little tenuous...)

Challenging the men - gender differences in sport

It's yet another jaw-dropping performance from a woman who only came to the sport late.  Wellington is, if we stick to the theme of the last few posts, a classic "late specializer", and in my opinion, a great example that talent goes a long way!  Not that she was idle in her youth - she describes herself as sporty, but her focus on triathlon, following a sabbatical in Nepal, is as recent as 2007.  Within years, she's not merely winning, she's rewriting the sport's record books, and moving it into a new era.  The message she gives is not "you can be anything you want to be", but rather "It's never too late to be great!"...if you have the ability, that is..! 

And with her latest performance, the inevitable question is again whether Wellington is in the process of closing the gender gap, and how long will it take for a woman to win a men's race outright?

This was something I looked at last year, when we named Wellington as our Sportswoman of the Year for 2010.  Wellington is well on the way to 'defending' that title, but what I have described below is a similar discussion and analysis of her times relative to men's performance, because I've been asked about it a few times this morning already, and it's a pretty intriguing question in sports sciences.

Wellington in the open race - placing in the overall race

Wellington has rarely been outside the top 10 overall of her races - 7th in Roth, 7th in Korea, 8th in Arizona and now 8th in Port Elizabeth.  Her marathon times in some of her wins a regularly bettered by only a few men in those races.

The problem is that these direct comparisons present some misleading possibilities.  For example, if you took Paula Radcliffe's marathon WR of 2:15.25, she would place 13th in yesterday's Rotterdam Marathon, and 10th in London in 2010.

Yet, when you take that time and look at it against a larger group, you see that it ranks outside the top 400 PER YEAR (I recall that it was 473rd on the world lists for men last year), and outside the top 3000 in history! A once-off record can stack up well in a given race, but the same doesn't apply against the collection of races.

That's partly because a race like Ironman SA brings a good elite field, but it lacks depth - the best men are spread across dozens of races, and gather together only in Hawaii.   The way the competitive racing circuit is set up, it facilitates a "spread" of ability, not a concentration.

Similarly, the London Marathon has an amazing elite field, but it's only 6 or 7 deep, with the rest choosing Rotterdam, Paris and Boston to race in.  So once you get below 8th or 9th, you move away from the cream of the men's sport, yet you're comparing them to the very best woman in history.  And that's why the best comparison will come from either overall comparisons or at the pinnacle event, Kona in Hawaii.  And incidentally, there, Wellington finishes in the 20s - 22nd in 2009, for example, which is still exceptional.

By time - Wellington's times relative to men

The other way to compare performances is to look at time.  This also brings some problems, and it's particularly difficult to benchmark female performances in a sport like triathlon.  Three disciplines, differing conditions from one race to the next and within each race (thanks to the length), and race tactics make direct time comparisons less reliable than for track where records are often structured and paced.

You can do this for track and field, however.  The graph below shows the comparison between the men's world record and the women's world record for the track events.  You'll note that all women's records are between 9% and 13% slower than the men's times.  Given the long history and the relatively standardized conditions (for world records, which are almost always set in ideal conditions), these numbers show pretty clearly that men outperform women by around 10 to 11%.  Radcliffe's marathon record, ranked outside the top 3000 all-time, is 9.2% off the men's WR.

Now, let's look at Wellington's performances in the Ironman, as shown by red symbols below.  First, what is her place in history compared to other winners?  Below is a graph that compares the winning performances at Kona for women to the men's winning performances since 1995 (three generations of athlete).  This is done so that the varied conditions (and Kona can be very different, with heat and wind) are somewhat controlled for.

The difference, you can see, is pretty much the same as for the track and field events, with a few exceptions, where women are well down on the men (upward of 13%).  Wellington arrives in 2007, and goes from 10.8% to 9.7% to an amazing 6.7% slower than the men in her three wins.  In 2010, Mirinda Carfrae was only 9.8% off the men's winner.

Clearly, Wellington has been to the Men's Kona winner what most female track and field world record holders are to their male counterparts.  She is, from that point of view, in exactly the right place compared to the best men, and edging the event forward.

There are also other exceptional performances - the blue triangle above in 2002 is Natascha Badmann's 9:07 performance, which was only 7.5% slower than the men's winner that year (Timothy de Boom in a relatively slow 8:29:56).  This Badmann performance also shows up the flaw in this analysis - year by year is too variable - was that men's performance just very weak that year?  Did race tactics affect it?  More than likely...The fact that two years later, Badmann wins the race a full 15% slower than the men's winner confirms this - year on year comparisons of winners leaves some variability, and that's why a more "rigid" benchmark is needed.

All-time comparisons from Kona

So let's use the men's course record as the benchmark. There are problems with this comparison, too, of course.  For one thing, variable weather from one year to the next can blow out the differences when you compare isolated performances with a 'best ever' performance, but I think the trend will be revealing when combined with what we discussed above. You could do this same exercise with the average of the men's times, incidentally, and subtract about 3% off the difference.

So, in 1996, Luc van Lierde of Belgium won the race in 8:04:08, which still stands as the record today.  Comparing all the women's winning times since 1995 to that performance, Wellington's impact on the sport stands out a little more, as you can see in the graph below.

This graph suggests to me that Wellington has moved the sport into a new era for women - where the gap was previously 12%, she's moved it down to 10%.  That may seem a small improvement, but bear in mind that if the world record in the marathon were improved by 1%, it would be 1 minute 14 seconds faster.  So Wellington really has pushed the event forward.

Her Roth performance is 6.1% slower than the men's record, and yesterday in South Africa, she was only 5.8% behind the winner.  Those are remarkable performances, but again, the nature of single races does sometimes allow the very best (Wellington) closer to a 'diluted' men's field than would be the case against the very best men.

What does seem true, however, is that Wellington is getting better.  Therefore, she may well be primed to break the Ironman record in Kona this year - certainly having moved the overall Ironman record faster by many minutes, her 8:54.02 seems ready for revision.  If that happens, she may well bring the women's record down to within 9%, maybe even 8% of the men's time, and that would confirm what an extra-ordinary athlete she is.

Quite apart from all this is her media-friendly personality, her desire to engage and support the growth of the sport - she's a champion that the sport needs, and perhaps every sport wishes it could have.  Let's see what she produces next!

Marathon stats from around the world

This past weekend also saw the start of the Spring marathon season, with some quick racing in Rotterdam and Paris.  Next week are the big two races of the spring, London and Boston, and we'll be covering those with our usual analysis.

But until then, some interesting analysis came out yesterday, courtesy Ken Nakamura.  He looked at the winning times from all the major marathons and determined that Rotterdam is now the fastest marathon in the world, with Berlin and London in second and third.

Perhaps even more interesting, the sub-2:06 barrier is now the standard for elite marathon running - 24 men have cracked this barrier, the latest being Wilson Chebet in Rotterdam (2:05.27).  Compare this to 2:07, which has been broken by 75 men, and you see that the gap between good and great now lies around 2:06!

2:08, which used to be a world-class performance, is now comparably mediocre, such has been the explosion in performance in the last decade.  The rest of the world need to pay attention, because when the standard shifts, so too much expectation, or you're in danger of being left behind.  This is partly the case in SA, where we haven't improved nearly to the same degree, yet celebrate 2:10 marathons as world class.  2:06 gets you to the banquet, not 2:08...

The series on training, talent and champions resumes later this week (I hope!).

Ross