Do running shoes reduce injuries?

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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)

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This week’s Jockology column is now posted on the Globe and Mail website. It takes on a topic that’s reasonably familiar to readers of this blog: whether the “right” running shoes will reduce your risk of getting injured:

[…] “I was completely convinced that impact is something bad, and pronation is something bad, and I wanted to show that,” recalls Benno Nigg, a biomechanics researcher and co-director of the University of Calgary’s Human Performance Lab, who helped shape the original theory of pronation.

The initial studies were promising. Specialized running shoes, designed to address different degrees of under- or overpronation, could indeed reduce the impact forces shooting up through the legs of runners in lab testing. In the United States, sales of these high-tech shoes jumped from 25 million pairs in 1988 to 40 million in 2009, and growth was similar in Canada.

But there was just one problem: Running injuries didn’t disappear…[READ THE REST OF THE ARTICLE]

I also spoke to Michael Ryan, the researcher whose UBC/Nike randomized trial of different shoe types made a huge splash last year:

“We were a bit nervous, because … if you see someone who is highly pronated, putting them in a neutral shoe may be a recipe for causing more pain,” acknowledges Michael Ryan, the study’s lead author, who is now a postdoctoral researcher at the University of Wisconsin.

He needn’t have worried…

In terms of practical advice, the article ran with a sidebar that doesn’t appear to be posted online, so I’ll add it here:

Picking a running shoe
Shoe researchers Benno Nigg and Michael Ryan agree that comfort is a good starting point for picking a running shoe. Some other factors to consider:

  • You can only assess comfort by actually running in the shoe. Many running stores will allow you to run around the block or on a treadmill.
  • Don’t ignore fit in favour of fancy shoe features. Find a brand and/or model that fits the specific characteristics of your foot, such as width.
  • Dr. Ryan’s research suggests that heavier, bulkier shoes may be associated with more injuries. So all else being equal, choose a lighter shoe.
  • If you’re making a radical switch (trying minimalist shoes for the first time, for example), take it slow. Expect to spend four to six months adjusting to the new shoes.
  • If you’re currently running successfully in a certain type of shoe, stick with it!

Metabolism rises for 14 hours after hard exercise

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)

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Pretty cool study from David Nieman’s group at Appalachian State, just published online at Medicine & Science in Sports & Exercise. We’ve all heard the various theories about how exercise pumps up your metabolism so you’re burning extra calories throughout the day. The only problem is that attempts to measure this have produced all sorts of conflicting results, primarily because it’s such a pain to measure. You have to hook people up to complicated metabolic measuring equipment over and over, control for whatever random activities they do throughout the day, and so on.

This new study has two big strengths. One is a fancy, newly built “metabolic chamber” — basically a tiny room where everything that goes in and out is strictly controlled, including oxygen and carbon dioxide. Measuring the amounts of oxygen and CO2 going in and out (along with exact knowledge of the food going in and human wastes going out) allows the researchers to calculate exactly how many calories the subjects burn while they’re in the room.

And the second strength is that they were pretty hard-ass about the study protocol. The subjects (10 healthy young men) spent two 24-hour periods in the metabolic chamber: one where they did basically nothing, and the other where they did nothing except one 45-minute cycling session at about 70% VO2max:

At 8:00 am, subjects were sealed in the chamber and asked to stay in a seated position unless they needed to use the restroom or perform other necessary daily activities (e.g. washing hands, brushing teeth, etc.). Breakfast was served through an air lock passage at 9:00 am. On rest days, subjects remained in a seated position from breakfast until 12:30 pm when they were asked to get up and stretch for 2 minutes. On both rest and exercise days starting at 12:30 pm, subjects were asked to get up and stretch for 2 minutes every hour until 6:30 pm… Subjects were asked to remain in the seated position until 8:00 pm, at which point they were able to relax and lay down but not go to sleep. Bed time was at 10:30 pm, and subjects were asked to lie down even if they were not sleeping.

Hard core! Anyway, getting (finally) to the point: exercise boosted metabolism for the next 14 hours, burning an extra 190 calories in addition to the 519 calories burned by cycling (i.e. 37 percent extra). Note that it was vigorous exercise, which the researchers believe is important — some of the earlier studies that didn’t find any metabolic boost used more leisurely protocols (e.g. 50% VO2max). Here’s what the data looked like:

How much will I slow down in my late 30s?

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)

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While I’m clearing out my mailbag… I got a question from a 800-metre runner in his mid 30s asking about how quickly he should expect his (and his competitors’) times to decline. It’s an interesting question that can be approached in a number of different ways — age-group records, which obviously depend on outliers; population-level cross-sectional studies; individual longitudinal studies — and all give different answers.

I cover this in a fair amount of detail in my book, but a couple brief points: numerous studies over the past three decades have found that cross-sectional declines tend to be steeper than longitudinal declines. That makes sense: the cross-sectional data gets weaker and weaker as you get to higher ages because there are more injuries and fewer people interested. (The latter factor is interesting in its own right: there’s evidence, albeit in mice, that the “impulse to exercise” declines with age. So it’s not just that people get busy or bored with competition, they may also have less intrinsic drive to compete.) Anyway, the point is: if you remain healthy and continue training at the same relative intensity (big “ifs” in both cases), you should expect to be able to beat the “average” decline represented by data like age-graded tables.

Speaking of which, here’s some data. The WMA age-graded table expect that you don’t start slowing down at all until you hit 35. At that point, the decline until your 40 appears to be linear. For comparison, I’ve plotted the times put up by the inimitable Johnny “Twilight Zone” Gray:

Gray was obviously a one-of-a-kind performer in many respects. The question is: was he a freak because he was still capable of running 1:45 as a 39-year-old? Or was he a freak because he was still interesting and willing to train at the level required to run 1:45 when he was 39? How many other 1:42 guys could have done the same if they’d tried? We don’t really know the answer to these questions, but the general feeling among researchers that I’ve spoken with is that the fundamental physical decline is much less steep than we previously believed. It’s more about training and motivation (and, of course, injuries).

Alcohol-free beer as a recovery drink: better than what?

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)

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Way back in October, I got an e-mail from Glenn, a running coach at Concordia University in Montreal, wondering whether alcohol-free beer might make a good post-workout recovery drink. He made a pretty convincing case for it, and I promised to look into it and get back to him with my take…

Fast forward to February (with his e-mail still in my to-do list), and there’s a big flurry of articles about Bavarian brewer Erdlinger’s “Alkoholfrei” beer being promoted as a sports recovery drink:

Promoted as a “sports and fitness drink,” Erdinger began targeting athletes in 2001 in Europe with an advertising campaign featuring a pair of triathletes. Its popularity quickly grew in Europe, where it’s often distributed for free in the finishing area of sporting events.

Sure enough, if you go to the Alkoholfrei website (“100% regeneration”), they have profiles of all the triathletes and biathletes that they sponsor.

So is it justified? Well, it depends on what you’re comparing it to. Most of the articles I’ve seen line it up against sports drinks — the equivalent of classic Gatorade. And actually, in that context, it doesn’t do too badly. It’s a drink with some carbohydrates in it, and not much else. But is anyone really recommending that athletes should pound some Gatorade after their workouts? In fact, as Glenn pointed out in his e-mail to me, a better comparison would be with chocolate milk, which is often touted as an “ideal recovery drink” because it contains protein in a roughly 1:4 ratio with the carbs it contains.

Here’s how some of these options stack up, in grams per 100 mL:

Carbs Protein Fat Calories
Alkoholfrei 5.3 0.4 0 25
low-fat choc milk 10.4 3.2 1.0 63
Original Gatorade 5.8 0 0 21
Gatorade Recover 2.9 3.3 0 25

Now, there are some other details like electrolytes, and Alkoholfrei likes to point out that it has vitamin B12 and so on — but to me, these are irrelevant details. When you’re recovering after a workout, you need fluid, carbohydrate and protein. If you get that, it’s highly unlikely that you’re NOT going to get the electrolytes you need.

So the verdict: Alkoholfrei looks a lot like plain old Gatorade — primarily carbs, though it does have a bit of protein. As a recovery drink, it’s not bad, as long as you’re also eating some food to give you some protein. But it’s not “complete” in the way chocolate milk is hyped to be. I guess the conclusion is sort of like those breakfast cereal commercials: alcohol-free beer is “part of a complete, balanced post-workout recovery protocol.”

(Last thought: of course, calories matter too — and that depends on how vigorous your workout was. Unless it’s a particularly vigorous workout, you really don’t need any recovery food/drink at all beyond whatever meal is coming up next — or at least, you certainly don’t need 500 mL of chocolate milk or three alcohol-free beers!)

[Thanks again to Glenn for putting the topic on my radar.]

Running halts mitochondrial aging (and hair loss!) in mice

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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)

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Scientists don’t know exactly why or how we get old, but they have a few theories. One of them is that mutations in mitochondrial DNA gradually accumulate until body systems stop working properly — a theory supported by the premature aging observed in mice genetically engineered to rapidly accumulate mutations in mitochondrial DNA. Yesterday, McMaster University researcher Mark Tarnopolsky‘s group published a paper in the Proceedings of the National Academy of Sciences in which these fast-aging mice ran on a treadmill — with extremely encouraging results:

[T]hose who had endurance exercise training three times a week looked as young as healthy mice while their sedentary siblings were balding, greying, physically inactive, socially isolated and less fertile. [press release here]

Sounds pretty good… and the changes weren’t just on the outside. In the exercising mice, their brains didn’t shrink, their muscles didn’t waste, their hearts didn’t weaken, they didn’t die prematurely, and so on and so on. Of course, mutations in mitochondrial DNA were still accumulating — but the basic cellular response to endurance training is that you increase the amount of mitochondria in your cells, so the researchers suspect that having lots of healthy mitochondria made the mice less susceptible to problems stemming from the mutations.

This isn’t the only theory about aging. Telomere length is another idea that has received a lot of attention recently, for example — but that too seems to respond dramatically to endurance exercise. Of course, conflicts of interest should be reported in studies like this: Tarnopolsky is a highly accomplished ultra-runner! 🙂