Month: November 2011

Posted on

Chris McDougall responds

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

[UPDATE: After a few further e-mails, it’s become clear that Chris misspoke in his original interview with me, and said he’d been struggling with plantar fasciitis for “two years” when he meant to say “two months.” This certainly makes a difference in my general sense of the extent to which it was misleading to write that he hadn’t lost a day of running to injury since then.]

I got an e-mail from Chris McDougall earlier today, asking that I correct what he sees as the errors in my post from a few days ago. Here’s his account of my errors:

there are several mistakes in your post about me. i’ve told the story of my bout with PF publically and often, as in the outside magazine interview below. your version is incorrect.

1/  i wasn’t “felled” by PF. in fact, i never missed a day of running because of it.during that period, i ran with many sources, including amby burfoot, matt carpenter, scott jurek, tony kupricka, david horton — all of them tough runners, most of the runs on hard trails.

2/ I didn’t have it for two years; it bothered me for a few months.

3/ i wasn’t ‘stressed out’ about it because the publication date was nearing; on the contrary, i was still researching and writing. i considered it a formative learning experience, which is why i’ve spoken and written about it many times.

4/ my training in 2006 was vastly greater than 2010/2011. in 2006, i hit 100 miles a week, including two 50-mile runs and several weeks of high altitude in leadville. last year, i averaged maybe 30 miles a week. i was traveling nearly non-stop, squeezing in whatever workouts i could manage.

Here’s an excerpt from the transcript of our interview in 2009:

Imagine the situation I’m in. Because two years ago, I start researching this book. And the whole purpose of the book, premise of the book is that I’ve discovered the secret of lifelong injury-free running. And in the middle of writing the book, I come down with this ailment. And I can’t shake it. And I’m thinking, you know, I’m about to go out and promote a book. And I got this stinking injury. And I spent two years [UPDATE: Chris misspoke and meant to say “two months”] trying to get rid of it.

His points number 2 and 3 are directly contradicted by that quote. Obviously I’m not inside his head (or his foot), so I don’t know which version is more accurate. But I think my original blog entry was a fair account of what he told me.

As for point number 1, I’m happy to believe him if he says he hasn’t missed a day of running due to injury since then. And I never said he did. But I certainly felt (and still feel) that the impression left by writing “I haven’t lost a day of running to injury since” is at odds with the fact that, during that period, he travelled (again, according to his 2009 interview with me) to see “doctors in Germany, in London, in Detroit, in Indianapolis, in California… all kinds of different people” in unsuccessful attempts to get rid of the injury. If that’s not being “felled” by an injury, I don’t know what is.

Finally, I’m not sure why he’s calling point number 4 an “error.” He suggested that his improvement from 2006 to 2010/2011 could be explained by his use of the 100-up. I suggested that an alternate (and in my opinion more likely) explanation was that he had four years of consistent running behind him, instead of one year of high mileage. Running is cumulative, and many runners experience episodes like this. Obviously I’m just speculating, as is he himself.

Ultimately, I’m disappointed by this exchange. As I said in the initial post, I think McDougall has a great story to tell that has resonated with a lot people. That story is strong enough on its own merits; it doesn’t need to be made better than it already is.

Posted on

Stats 101: interpreting medical studies

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

I have a new article over at the Men’s Health website that tries to explain a bit about how the process of “statistical adjustment” works in large observational studies, and what some of the pitfalls are. My favourite example from the piece: a 2009 study of over half a million people that found that red meat intake is associated with increased risk of death — even after “adjusting” for potentially confounding factors like age, education, race, BMI, smoking, exercise, vegetable consumption and so on. Needless to say, that study got lots of press at the time. But when you dig into the study’s stats (as Stanford prof Kristin Sainani pointed out to me), you find out that red meat also increases your risk of sudden accidental death from causes like car crashes and guns!

“Unless red-meat eaters are swerving to avoid cows, that doesn’t make any sense,” Sainani says. Instead, the most likely explanation is that red-meat eaters take more risks in other areas of life. But the study didn’t collect any data on the driving habits and gun collections of its volunteers, so the researchers were unable to adjust for these factors—and as a result, the conclusions were skewed.

Another interesting nugget is a rough estimate of the size of effect needed to be fairly sure you’re not seeing the effects of residual confounding, according to statistical simulations:

Bad data can easily generate an apparent risk increase of up to 60 percent, according to a research paper on statistical adjustment published in the journal PM&R. Effects bigger than that are very difficult to explain without serious errors in the design of the study.

Anyway, check out the whole article for more!

Posted on

After New York: how did marathoners get so fast?

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

Another major marathon, another jaw-dropping course record — pretty much what we’ve come to expect in 2011. Geoffrey Mutai’s 2:05:06 at yesterday’s New York Marathon, a course record by 2:37, continues the string of unbelievable performances from Boston, London, Berlin, Frankfurt and so on that have redefined our (or at least my) perceptions about what’s humanly possible at this distance. For a great post-race look at what’s going with the marathon, check out David Epstein’s piece at Sports Illustrated (and for more background, read Ross Tucker’s Science of Sport piece from last week).

Epstein gives a nice overview of the various forces that are converging to give us all these 2:03 marathoners — most obviously money (more of it in marathons, less of it on the track), which is bringing talented runners to 42.2K earlier in their careers. But I just wanted to highlight two quotes from his piece. First:

“I think people are starting to figure out the training and physiology better,” said American Dathan Ritzenhein, who made his marathon debut in New York in 2006 at the age of 23 and finished ninth in the Olympic marathon in ’08.

And second (on the topic of whether all these runners moving to the marathon at a young age will end up having shorter careers than guys like Geb and Tergat, because of the inevitable physical toll of the distance):

Krista Austin, a physiologist who works with pro runners, thinks that this generation of young Kenyan marathoners will have a shot at long careers because “the Kenyans are just starting to do some of the basic [injury prevention] things, like stretching and massage and Pilates.”

The juxtaposition of these two quotes made me smile a bit. One on hand, Ritz saying that marathoners are getting faster in part because of greater understanding of physiology. On the other hand, Austin is correctly pointing out that the runners who are most obviously the fastest (the 20 fastest male marathoners of 2011 are ALL KENYAN) are barely taking advantage of even the most rudimentary suggestions of sports science. If we’re judging by results, we might want to think carefully about which approach we emulate!

Obviously it’s a very complex issue, and I won’t even get into the whole genes/environment question. But in addition to money, I think Epstein (citing Gabriele Nicola, the Italian coach of several of the top Kenyans) nails a vital point:

If one person can run fast, well, dammit, you can train or race with them, and you can, too. As much as we might say this is “in your head,” if it’s in your head, it’s in your body, at least within limits.

 

Posted on

Chris McDougall on “the one true way” to run

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

[UPDATE Nov. 8 : Chris McDougall sent me an e-mail asking that I correct several errors in this blog entry. His description of the errors, along with my response, is here.]

I’ve had a few e-mails asking what I thought of Chris McDougall’s piece “The Once and Future Way to Run” in this weekend’s New York Times Magazine, so I figure I might as well share those thoughts here.

1. Chris is a great storyteller and an engaging writer. I really enjoyed Born to Run, and I enjoyed this piece too. I think the running world is better off now that there’s greater awareness of the potential benefits of running barefoot or in minimalist shoes, and people have another option in the search for a running approach that works for them. I’d go so far as to say that McDougall has done more than anyone else in the world over the past two years to bring new people to running and create excitement about its possibilities.

2. What about the science in the article? I can’t really critique it, because there isn’t any science there — it’s all anecdote. For a thorough and balanced take on what the science does (or, more accurately, doesn’t) tell us about the quest for running perfection, read Pete Larson’s response to the article. He’s the evolutionary biologist quoted in the opening scene of McDougall’s article. Larson’s cautious middle ground is probably not what you’d expect if you’d just read McDougall’s article without knowing anything else about Larson.

3. What about W. G. George’s 100-up exercise, a century-old drill that McDougall suggests may be the “one true way” to develop perfect running form? This is where I start rolling my eyes, when he attributes a series of personal best performances to this magic drill:

“I don’t get it,” [he says at one point in the article,] “I’m four years older. I’m pretty sure I’m heavier. I’m not doing real workouts, just whatever I feel like each day. The only difference is I’ve been 100-Upping.”

Oh, please. For one thing, four years ago was, by his own account, roughly when he finally “learned to run” for the first time. If he’d been unable to run for years, and then learned to run, his improvement now compared to four years ago is likely due to something we call “training.”

Incidentally, the 100-up is a drill that modern runners call the “running A.” Virtually every competitive runner I know has done it at some point, and it’s a basic staple of every elementary school track camp. I was first introduced to it more than 20 years ago. So does that mean that McDougall is right, that it’s the secret that makes good runners fast? Of course not. It’s one of the many, many tiny ingredients that can add up to running success. There’s no secret, and no short cut.

4. The one part of the article that made me kind of angry was this passage, about McDougall’s visit to the Copper Canyon in Mexico that led to Born to Run:

I was a broken-down, middle-aged, ex-runner when I arrived. Nine months later, I was transformed. After getting rid of my cushioned shoes and adopting the Tarahumaras’ whisper-soft stride, I was able to join them for a 50-mile race through the canyons. I haven’t lost a day of running to injury since.

I actually interviewed McDougall back in 2009, shortly before Born to Run came out. And that’s not the story he told me. Here’s what I wrote then:

Long plagued by an endless series of running injuries, he set out to remake his running form under the guidance of expert mentors, doctors and gurus. He adjusted to flimsier and flimsier shoes, learning to avoid crashing down on his heel with each stride and landing more gently on his midfoot. It was initially successful, and after nine months of blissful training, he achieved the once-unthinkable goal of completing a 50-mile race with the Tarahumara. But soon afterwards, he was felled by a persistent case of plantar fasciitis that lingered for two years. “I thought my technique was Tarahumara pure,” he recalls ruefully, “but I had regressed to my old form.” Now, having re-corrected the “errors” in his running form, he is once again running pain-free.

I’m in New York right now, and won’t be back home until Monday night, otherwise I’d see if I can dig up my actual notes from the interview. But I remember McDougall telling how stressed out he’d been, because he’d spent all this time working on a book about the “right” way to run — but as the publication date loomed ever nearer, he’d been chronically injured for two years. It was only shortly before publication that he was able to get over the injuries and start running again.

So does this prove that barefoot running is a sham? Of course not. Injuries happen, with or without shoes. But it points to a fundamental dishonesty in the way the story is being told. He’s not disinterestedly sharing with us the results of an experiment he performed on himself; he’s deploying all his rhetoric to make as convincing a case as possible for one side of an argument that (as Pete Larson explains) is much more nuanced than he pretends. I’m not a big fan of “science by anecdote” under any circumstances — but if you’re making up the anecdotes, then what have you got left?

Posted on

Dehydration in the lab vs. the real world

THANK YOU FOR VISITING SWEATSCIENCE.COM!

As of September 2017, new Sweat Science columns are being published at www.outsideonline.com/sweatscience. Check out my bestselling new book on the science of endurance, ENDURE: Mind, Body, and the Curiously Elastic Limits of Human Performance, published in February 2018 with a foreword by Malcolm Gladwell.

- Alex Hutchinson (@sweatscience)

***

The “right” amount of hydration during exercise is a hot topic these days. For years, lab studies showed that if you forcibly dehydrate someone and then stick them on a treadmill, their performance suffers. But more recently, “real-world” studies (like the one I blogged about here) have shown that in many cases, the fastest finishers in races tend to be the most dehydrated. The difference, according to researchers like Tim Noakes, is that in the real world your brain is able to make pacing decisions that keep your body in a safe state (using the thirst mechanism); on a treadmill at a fixed pace in a lab, your brain is cut out of the loop.

The result is that there are two bodies of research — lab and field — that appear to be answering the same question (how much should we drink?) but that produce completely different answers. So it’s nice to see a study from the “lab” camp that tries to bridge this gap by doing some experiments on an outdoor trail run. Researchers from the University of Connecticut had 14 runners perform two 12K trails runs, one in a hydrated state and the other in a dehydrated state. Here’s what they found:

Pretty straightforward, right? The runners were slower when they were dehydrated. As expected. Case closed. And we should disregard those inconvenient studies that found that faster runners in real races are more dehydrated, according to the researchers:

Although some field studies have found runners to be extremely successful despite considerable body fluid losses, these runners were not compared with a control condition where these same runners remained more optimally hydrated. Therefore, one cannot conclude that performance in these elite runners may have been enhanced if they had maintained or at least attenuated some of their fluid losses while racing.

But hang on a sec. Does this new study really offer valid “field” conditions? Not quite. It may have been conducted outdoors, on nice trails in a local state park, but it nonetheless managed to reproduce all the usual problems of lab studies. First of all, the runners weren’t freely paced: they were instructed to run at a set heart rate, which imposes a rather arbitrary limitation. So they didn’t go slower because they were unable to keep the pace, but because they weren’t allowed to increase their heart rate. More importantly, the dehydrated runners weren’t allowed to drink or eat “high water content foods” for 22 hours before the test run! The result:

So what can we conclude from these results? If you subject volunteers to a punishing dehydration regimen before your experiment even starts, their performance will suffer. This is very important to bear in mind next time you’re stranded in the desert. But as for how much water you should drink during your next run, this study has basically nothing to say.

(I should point out that the researchers did measure a number of other physiological parameters in the study, like gastrointestinal temperature. This is useful data. They also argue that holding heart rate steady is useful because it’s “similar to how a cross country or track coach may advise their athletes to maintain a certain intensity level during a run.” Sure, I guess. But if that’s what they’re measuring, then why are they using the results to make claims about what happens in real-world marathons, where nobody starts after a full day of dehydration?)