Posts Tagged ‘running’

How many carbs do you need to max out your muscle stores?

January 23rd, 2012

My column in today’s Globe and Mail takes a look at some recent field research on carbo-loading the day before a marathon:

[…] To find out whether this revised advice works in practice, researchers in Britain followed 257 London Marathon participants for five weeks prior to the race, collecting data about their training and eating patterns. The runners had an average age of 39 and an average finishing time of 4 1/2 hours. The results were published in the International Journal of Sports Medicine.

Sure enough, day-before carbohydrate consumption mattered. Runners who ate more than seven grams of carbohydrate for every kilogram of body weight (g/kg) ran 13.4 per cent faster than a comparable group of runners who ate fewer carbohydrates but were otherwise identical in terms of age, body mass index, training and marathon experience. Surprisingly, the amount of carbohydrate consumed during the marathon didn’t matter as much. [READ THE WHOLE ARTICLE HERE]

Most people don’t realize what an enormous amount of carbohydrate you have to take in to maximize your glycogen stores — which is why only 12% of the runners in the study hit the 7 g/kg threshold. Trish McAlaster did a nice job with an accompanying graphic showing just how much you’d need to eat and drink to hit 5 g/kg (the average in the study), 7 g/kg, or 10 g/kg (which is the amount suggested for elite athletes). Note that I’m not suggesting you should actually eat four plates of plain pasta for dinner — this is just to put the amounts in context!

[CORRECTION: Reader Mike LaChapelle just pointed out that the math doesn’t add up in the graphic. The “threshold” lunch should include 500 ml of sports drink. That being said, I should clarify that I’m not recommending these menus as exactly what you should eat; it’s aimed at giving a sense of the quantities involved. In real life, I’d go for more variety, and include things like fruit and vegetables!]


Dathan Ritzenhein after his fourth place Trials marathon

January 14th, 2012

At the U.S. Olympic Marathon Trials, where the top three book tickets to London, fourth is the loneliest place. Here’s my post-race interview with an emotional Dathan Ritzenhein:

He ran a new personal best of 2:09:55, breaking 2:10 for the first time and capping a remarkable comeback from a seemingly never-ending string of injuries. But silver linings don’t matter when you finish fourth at the Olympic Trials – and for Dathan Ritzenhein, the frustration of being hobbled yet again by leg cramps could mark the end of his marathon career.

“It’s the same thing that’s happened in other marathons,” Ritzenhein said after the race, struggling to contain his emotions. “Maybe I’m forcing it. Everybody wants me to be a marathoner. And I want to be a marathoner. But right now maybe it’s not in the cards.” […]

Read the whole interview here.

Meb in Skechers vs. Meb in Nikes

January 4th, 2012

Meb Keflezighi is an Olympic medallist and a New York Marathon champ. So when he signed with Skechers last summer, observers were… surprised. The company’s new “Go-Run” line promises to make you switch to a mid-foot strike: “The Way You’re Supposed to Run.”

So does it work?

Krista Austin, an exercise physiologist and longtime friend of Meb’s (read about her role in “rebuilding Meb” before his 2009 New York win here), points out this opportunity to compare strides. Here’s Meb in Nikes:

And here’s Meb in Skechers:

Can you see a difference? Any improvement?

Men’s marathon: how much faster is it getting, and why?

December 22nd, 2011

Marathoners are getting faster — that’s no secret. Here’s the progression of the fastest men’s marathon in each year between 1969 and 2010:

But looking at the leading time is a somewhat narrow approach, since it just reflects the freakish talents of one individual in each year. So here’s data, from a new analysis by researchers from the University of Milan in the Journal of Strength and Conditioning Research, showing the average of the top 200 times for the same time period:

So the basic trends are similar, but not identical. Look at the last three years, for example. From the top time, you might think marathoners are getting slower; but the second graph shows clearly that — as anyone paying attention to the marathon lately can attest — the depth of fast performances has been increasing steadily and sharply. I’ll bet the 2011 numbers will continue that trend.

The average data also shows a few inflection points where the rate of improvement has changed. There was rapid improvement until 1983, then a leveling off until about 1997; decrease again until 2003, then a little hitch for a few years, and now steady decrease again.

So what explains the changes? We can speculate about the role of money, science, and training… But as Amby Burfoot pointed out in his take on this study, it’s hard to get away from this stat:

[I]n 1997, East Africans nabbed just 29 percent of the top 200 times. For 2010, the corresponding figure was 84 percent.

One other interesting nugget: during this time period, the top time improved by about 5 seconds per year, while the average of the top 200 improved by about 10 seconds per year. So this means that (a) competitive depth is improving, and (b) in another 50 years or so, the 100th ranked marathoner in the world will be faster than the top-ranked marathoner of that year.

Which “rules of running” should you break?

November 28th, 2011

Forgot to mention this earlier — I have an article in this month’s Runner’s World called “Breaking All the Rules,” which is now available online. Basically, I had a chance to chat with a bunch of veteran coaches — Jack Daniels, Frank “Gags” Gagliano, Roy Benson, Jeff Galloway, Hal Higdon and Pete Pfitzinger — and ask them which “rules of running” they’d recommend not following blindly. Here’s one example:

THE RULE: Do prerace strides
For generations, runners have followed the same rituals to warm up before races or workouts: Start with some jogging, move on to a little bit of stretching, then perform a series of “strides”—short sprints lasting about 10 seconds that get your heart pumping and kick-start the delivery of oxygen to your running muscles. But do these timeworn rituals really help us perform better? Jack Daniels, Ph.D., isn’t convinced. “What I most often see at races is a bunch of runners striding up and down at a speed that is clearly faster than the coming race pace,” he says. Since these strides are the last thing runners do before starting the event, that inappropriate pace is fresh in their minds. “And when the gun finally sounds, they ‘stride’ or sprint right out.” The result: a way-too-fast start followed by an inevitable crash.
HOW TO BREAK IT: For shorter events like 5-K and 10-K races, jogging just long enough to get a good sweat going is all you need to do, says Daniels. (For longer races, you can get away with even less: Run the first mile of a half or full marathon as your warmup.) To get the oxygen-boosting benefits of strides without skewing your pace judgment—and screwing up your race result—try a sustained two-to three-minute effort 10 minutes before starting the race or workout. Run it slightly faster than your half-marathon pace, or at a speed that feels moderately hard. You should not be sprinting.

Other topics covered include stretching, the length and pace of your long run, having a recurring weekly training structure, back-to-back hard days, cross-training during injuries, and so on. I should emphasize: none of the coaches are suggesting that existing rules-of-thumb are 100-percent bad. They’re just worth thinking about to make sure that they really do make sense for your personal situation and goals. For example, Higdon questions the wisdom of the 10-percent rule — he’s not saying that you should never increase your mileage by 10 percent; he’s just saying that sometimes it might make sense to increase it by more, sometimes by less, so you shouldn’t follow the rule blindly.

Cadence in elite runners increases as they accelerate

November 21st, 2011

One quick graph from a new study by Robert Chapman and his collaborators at the University of Indiana, just published online in Medicine & Science in Sports & Exercise:

This is data from 18 elite runners (12 male, 6 female), showing their stride frequency as a function of speed. For reference, 3.00 Hz corresponds to 180 steps per minute; 3.3 Hz corresponds to about 200. On the speed axis, 4.0 m/s is 4:10 per km, and 7.0 m/s is 2:23 per km. In other words, these are FAST paces. The key point: they get faster, in part, by quickening their cadence. There’s no magic cadence that they stay at while lengthening their stride to accelerate.

Interesting wrinkle: the women have faster cadence than the men at any given speed. Chapman assumes this is partly due to the fact that the men are taller — but even normalizing by height doesn’t quite erase the difference. (And that even ignores the argument that, as I blogged about here, cadence should be proportional to the square root of leg length, not leg length itself.) The remaining difference, Chapman hypothesizes, could be due to “application of greater ground forces by the men or differences in muscle fiber type distribution.” This makes sense: if you’re stronger (as the men, on average, will be), you’ll have stronger push-off, longer stride, and thus shorter cadence at any given speed. But it seems pretty clear that height plays at least some role.

If the 100-up isn’t the secret, what is?

November 11th, 2011

I’ve had some interesting e-mail exchanges over the last few days after I expressed my skepticism about the merits of the sudden enthusiasm for the 100-up exercise. Basically, my position was (a) sure, it’s a perfectly good form and/or conditioning drill, which is why it has been in pretty much continuous use for decades, but (b) I didn’t see any reason to think it was “the secret,” or any more useful than other form drills, simply because Walter George said he used it. The mere fact that someone is fast and does a particular drill is a pretty slender reed to build a training program on — and if that’s the yardstick, I pointed out to one person with tongue firmly in cheek, then I should be considered more qualified than Walter George to dispense advice, since I’ve run considerably faster than him.

Well, Justin called my bluff:

Great points all around [he wrote,] so here’s a question for you: if you had to start somewhere to learn running form — and you couldn’t afford a coach — where would you start?  What exercise would advance you the most in the shortest period of time?

That’s an excellent question. And a difficult one. So here’s my attempt to answer — or rather, to explain why I don’t have a simple, easy-to-package-and-sell answer.

The thing is, I’m still not convinced that most people do need to learn running form. I worry that all these articles about the necessity of learning the “one true way” to run are convincing people that they shouldn’t risk heading out the door in an untrained state to try this enormously complex activity.

Of course, some people definitely do need help with form. I watched the New York Marathon last weekend, and yes, there were some funky strides going past after the leaders were gone. So how do we fix those strides? Well, that depends on what’s wrong with them. Some people are leaning too far forward, others are leaning too far back. Many are overstriding, but a few are understriding. Some people are flapping their arms around like birds, others are barely moving them at all. It’s not the same fix for all of them.

Now, what Justin’s looking for isn’t a fix for a particular problem; he’s looking for a way to build the ideal stride from the ground up. And for that, maybe the 100-up is as good a place to start as any. I don’t have another exercise that I think is a “better” way to start developing a perfect stride, because I’m skeptical of the value of this perfect stride. In a sense, I’m just like Walter George in that I’m captive to my own experience and development. The way I learned to run was by heading out the door and trying it, then gradually adjusting along the way based on what felt good. That’s also how most of the people I know learned to run. Would we have been better if we’d been taught the “right” way to run right from the start? It’s possible.

By no means am I dismissing the benefits of optimizing running form. As I’ve written elsewhere, I think the single most common mistake people make is overstriding, which can often be addressed by quickening your cadence. I just have a nagging sense that form work has acquired enormous importance that is out of proportion to its value, when the real barrier for most beginning runners is still aerobic fitness. It reminds me of one of the most famous passages from Once a Runner:

And too there were the questions: What did he eat? Did he believe in isometrics? Isotonics? Ice and heat? How about aerobics, est, ESP, STP? What did he have to say about yoga, yogurt, Yogi Berra? What was his pulse rate, his blood pressure, his time for the 100-yard dash? What was the secret, they wanted to know; in a thousand different ways they wanted to know The Secret.


After New York: how did marathoners get so fast?

November 7th, 2011

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.


After the Toronto marathon

October 17th, 2011

I’m back online after a very busy three days at the Scotiabank Toronto Waterfront Marathon. I spent Friday and Saturday at the marathon expo, where I gave a couple of Science of Running talks, sold some books, and had a chance to talk to a whole bunch of Sweat Science readers. Those of you who were racing, I hope your day went well and you weren’t too buffeted by the winds!

This morning, I had the opportunity to ride in the truck driving in front of the leaders. My plan was to ride until about 20K, then hop out to follow the Canadians for the rest of the race. As it happened, Reid Coolsaet foiled my plan by hanging with the Kenyan and Ethiopian leaders even though they went out at a sizzling sub-2:07 marathon pace. I figured I’d wait until he blew up — and given the splits of 30:16 (10K), 1:03:58 (21.1K) and 1:31:38 (30K — seven seconds faster than the Canadian 30K record, as it happens), I kept thinking that would happen any minute. But it never did. Despite fighting a brutal headwind for the last 7K or so, Reid held on for third place in 2:10:55, with his teammate Eric Gillis also dipping under the Canadian Olympic standard by exactly one second in 2:11:28.

It was an exciting and inspiring morning. And the best part about it was Reid’s seemingly crazy decision to go out on pace for a five-minute personal best. As Canadian Running magazine’s Scott Leitch recounts, it was a last-minute decision. In fact, he was lying in bed last night, unable to sleep, mulling over the long-established plan to go through halfway in 1:04:40. Finally, he headed downstairs to the hotel bar to find his coach, Dave Scott-Thomas, and said:

I don’t want to sound stupid, but I want to get up front and mix it up. And I want you to tell me if that’s insane or not.

Scott-Thomas asked him how he felt. Reid said, “I feel great.” And that was that. In the end, it was a smart decision given the weather conditions. He was able to shelter in the lead group for nearly the whole race, whereas he would have been all by himself in the wind had he gone out at a more conservative pace. And it leaves Canadian running fans wondering: what will he run when he gets a shot under better conditions?

It was very difficult to get a clear shot from the media truck, but here’s a couple of minutes of footage from the start, the 28K mark, and the finish for Reid, Eric, and Dylan Wykes, whose windy 2:12:57 is a very good sign for his next crack at standard:


How limb length affects running cadence

October 6th, 2011

Okay, this is something I never expected to see: a study that uses walking on stilts to investigate the effect of limb length on optimal stride! First, let me backtrack. A few weeks ago, we had a spirited discussion on the blog about optimal running cadence, and one of the questions that came up was what role, if any, leg length should play in your cadence. Should Haile Gebrselassie (5’4″) and Paul Tergat (6’0″) run with exactly the same stride length?

Enter Max Donelan, the head of the Locomotion Laboratory at Simon Fraser University. He sent me an e-mail explaining that, all else being equal, running cadence (a.k.a. stride frequency) should be inversely proportional the square root of leg length. I’m going to quote the relevant section of the e-mail here, because he explains it well:

Some of your commenters were wondering about differences in size. Biomechanics knows how to normalize for size and we learned how from physicists – we use dimensional analysis and dynamic similarity. While there is some complexity for running, the same relative speed works out to be speed/sqrt(gravity*leg length). This is called the “Froude number”. Relative frequency scales with freq/sqrt(gravity/leg length). And, we expect that at the same relative speed, animals will use the same relative frequency. This turns out to be approximately true in animals ranging from mice to elephants. This matters for your article in two ways. First, it indeed says that smaller people should use a higher frequency at the same speed (although it is proportional to sqrt(leg length) and not directly proportional to leg length which is not intuitive for people). The second reason it is important is that we expect people that are approximately the same size, and running at approximately the same speed, to use approximately the same frequency. That is an explanation for why the best marathon runners use the same step frequency – they are all pretty physically similar and all running at about the same speed. If you can find a very tall winner and a very short winner, I bet one Canadian looney that their step frequencies are quite different.

Fascinating stuff. So of course, I looked up a few papers on the Froude number as it applies in running and walking (and there are, indeed, lots of them). One of them was the stilts paper, published a few months ago in the Journal of Experimental Biology.

Basically, they strapped on stilts to change the ratio of upper length to lower length, then measured oxygen consumption and muscle activation. Sure enough, limb segment ratio does make a difference in optimal speed and frequency — not that surprising, really. The more important message (for me, anyway) is that there’s a big body of literature supporting this idea that the Froude number applies to both walking and running, and thus that taller people should (if all else is equal) have a slower cadence than shorter people, by an amount inversely proportion to the square of leg length.

Oh, and one last point. Max wrote:

If you can find a very tall winner and a very short winner, I bet one Canadian looney that their step frequencies are quite different.

Here’s video of the classic example I cited before: Geb vs. Tergat in the last lap of the 2000 Olympics, running at the same speed but with different cadences. They start out striding in synch, but Geb is (as expected) striding more quickly. At a very, very rough estimate, it looks like it takes about 15 steps before they lock into synch again, which would imply that Tergat’s legs are about (16/15)^2 -> 14% longer than Geb’s. Considering that he’s 12.5% taller, that’s not a bad appromixation!

[Many thanks to Max Donelan for sharing his expertise!]