Why neither “normal” nor minimalist running shoes will disappear

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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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Which is better: a pill that 75% of the population can take, which produces wonderful benefits for 25% of those who take it; or a pill that 25% of the population can take, which produces wonderful benefits for 75% of those who take it? I was pondering this question while re-reading Peter Vigneron’s long, thoughtful piece about running form, from the June issue of Runner’s World. This passage, in particular, made me think:

Perhaps—and this, too, is speculative—the modern cushioned running shoe makes running easy for the modern runner. This seems like a good thing. Should millions of runners suddenly decide to change their form and then find that running is no longer a manageable activity, it would be a tragedy. The solution to an imperfect state of affairs ought not make things worse—it should not produce more injured, unhappy runners.

One of the common narratives you hear a lot these days is that modern running shoes are the product of an insidious corporate campaign to sell us useless shoes that effectively enslave us by weakening our feet. I find this conspiracy-theory stuff quite tiresome — shoes may or may not be good for us, and of course shoe companies want to sell us anything they can, but I have no doubt that the origin of what Pete Larson calls the “pronation paradigm” was well-intentioned. The simple but often overlooked point is that the shoes caught on. I’d bet that, in 10 years, the recent fad for “toning shoes” will be all but forgotten since they simply don’t work. But running shoes have had remarkable staying power — perhaps because, as Vigneron says, “the modern cushioned running shoe makes running easy for the modern runner.” Or at least some modern runners, some of the time.

Let’s say we accept that, in a perfect world, the barefoot running style is optimal for humans. What if in our postlapsarian modern society, a large proportion of us are simply not equipped to make that transition after decades of sedentary, shod living? Or we can make the transition, but it requires the careful, patient, dedicated, slightly obsessive six-month transition period that barefoot advocates scrupulously recommend? Given the staggeringly high numbers of people who can’t be bothered to do any physical activity, even so much as a brisk walk, despite the overwhelming evidence that it’s the single best thing they could do for all aspects of their physical and mental health, I suspect that the barriers to successful barefoot running will always limit it to a fairly small subset of population.

So that’s what my opening question was about: what if barefoot running is fantastic for a small segment of the population, while running shoes are hit-and-miss but accessible to a much larger portion of the population? What’s the “right” answer to how we proceed? Obviously I chose my sample numbers carefully (so that both versions of the pill help 18.75% of the population, if anyone’s checking the math), but I wonder what those numbers are in reality. How many people can barefoot running reach? How “bad” are normal shoes? In the end, the numbers don’t really matter — because there will always be some part of the population that can succeed with one approach but not the other.

Minimalism: three perspectives

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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Three interesting blog posts that anyone interested in the ongoing debate over minimalist shoes will be interested in:

First, Amby Burfoot had a brief Q&A with Irene Davis, a top researcher and barefoot advocate formerly at Delaware and now at Harvard, in advance of last week’s ACSM meeting. She discusses a few bits of upcoming research, and the freshest wrinkle from my perspective was a study on balance with and without socks:

It was determined that a thin pair of socks causes a statistically significant reduction in balance, suggesting that they filtered out important sensory information.

We often talk about barefoot running and minimalist shoes like Vibrams as essentially the same thing — but maybe there’s something intrinsically superior about going totally barefoot in terms of “dynamic stability.”

Second, Ross Tucker at the Science of Sport has a lengthy post that sums up his take on the barefoot debate starting with a very basic intro — perfect for those who want to get up to speed but haven’t been following the debate closely. This post sums up my own positions on the pros and possible cons of barefoot running absolutely perfectly, so I highly recommend it!

One interesting point that Ross makes is the difference between running and training for high performance. As he points out, it’s highly unlikely that our caveman forebears ever tried running 120 to 200K per week at relatively high speeds. At those training levels, muscle fatigue may become a limiting factor:

The third presentation in the symposium showed some really interesting evidence that the loading on the joints and bones was HIGHER as muscles fatigued.  This stands to reason, of course – muscle absorbs much of the impact force, and so tired muscle loses that ability, exposing the joints.

So those who are training for performance may struggle because of a muscle fatigue issue – the muscle is working differently, and harder in certain muscles, when barefoot, and that may be limiting.

Finally, Pete Larson at Runblogger has an epic post where he takes on the outspoken Asics researcher Simon Bartold (who I interviewed a few years ago for this article), with the discussion continuing in the comments section. What’s funny to me here is that I think the two of them are in pretty close agreement about the current state of evidence for (and against) normal and minimalist shoes — which is to say, there’s some suggestive biomechanical data but a complete dearth of convincing epidemiological or interventional data in either case.

The difference is in where they see the burden of proof. Bartold seems to hold minimalist advocates to a higher standard of evidence than he holds “current state of the art” shoes with a raised heel. Pete takes the opposite view:

Since evidence seems to be a popular word in this discussion, what evidence is there that this [shoes with raised heels] is safe? Shouldn’t the burden of proof be on the company making the product to show that it’s safe for the consumer? Isn’t this what drug companies have to do?

This is similar to what Blaise Dubois told me when I spoke to him a few months ago. But I’m not sure I fully buy that. Even if you accept all the evolutionary arguments marshalled in favour of barefoot running, I don’t think it necessarily trumps the experience of recent decades. Say you claim that sleeping in stuffy, poorly ventilated houses leads to respiratory infections, so we should sleep in the trees the way our ancestors evolved to do over hundreds of thousands of years. It might be true. But I’m not going to immediately give priority to a claim based on evolution (even if backed by logic and anecdotal support) and ignore the practical experience over the past few decades of people with whom I have a lot more in common than cavemen. These “modern” running shoes have been out there for the past ~20-30 years — and in that time, I’d bet that more people have run more miles successfully than in the previous couple of millennia cumulatively.

That doesn’t mean the shoes are “good,” or that we shouldn’t be eagerly and actively pursuing alternatives — just that they’ve earned a position as the default option, to be supplanted when something else is shown to be demonstrably better. If we’re using the lingo of drug trials, they’re the current “standard of care” that experimental treatments need to exceed in order to be adopted.

The priming effect: how a hard warm-up can help performance

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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Most people who do hard interval sessions will have noticed this mystery: why does the second or third interval usually feel easier than the first one? I always figured it had to do with “getting into the rhythm” or something along those lines. Whatever the reason, Pete Sherry — my main training partner for 2002-2004 — and I eventually decided that we’d run 2x400m in ~72 sec a few minutes before every workout, in the hopes of making the first interval feel easier. Our impression was that it worked, and we started doing it before races too.

It turns out there’s plenty of physiology behind this. If you suddenly start running at a hard pace, with no warm-up, it takes a while before your body can adjust to start delivering oxygen to your muscles at its maximum possible rate. That’s one of the reasons VO2max tests take 10-12 minutes, rather than simply involving a short, all-out sprint. It takes time for the blood flow to your muscles to increase, and for the enzymes that extract oxygen from the blood and oxidize fuel to ramp up their activity levels. A good warm-up gets this ramp-up process over with, allowing your body up to deliver more oxygen to muscles right from the start of the workout or race, and reducing the temporary oxygen debt.

Still, most people warm up with gentle jogging, flexibility drills, and some short sprints. But how about including a six-minute “hard” effort (above lactate threshold but below VO2max pace), about ten minutes before the start of your race or workout? Would that “prime” your oxygen kinetics even more? The challenge is as follows: a sustained burst of hard exercise (above threshold) definitely improves how quickly your body can process oxygen once the actual race starts; this effect can last for a half-hour or more. If you exercise too hard, on the other hand, you deplete your anaerobic energy stores (phosphocreatine), and metabolites build up in your muscles that may slow you down. Numerous experiments over the past decade have found conflicting results: depending on the precise details of the duration, intensity and recovery time following the “priming” burst, performance either increases, decreases, or stays the same.

A new cycling study just posted online at Medicine & Science in Sports & Exercise, from Mark Burnley’s group at Aberystwyth, adds some more data on finding the right balance. They used a six-minute priming bout, 10 minutes before the “race” — a formula that other studies have found to be effective. For intensity, they compared “heavy” (about 25% of the way between threshold and VO2max power) and “severe” (about 63%) priming bouts. The findings: “heavy” priming boosted oxygen kinetics and significantly increased time-to-exhaustion in tests ranging from ~2-10 minutes. “Severe” priming also boosted oxygen kinetics, but didn’t increase time-to-exhaustion, suggesting that the downside of depleted anaerobic reserves outweighed the benefits of more aerobic energy available early in the test.

So what does this mean in practical terms? It’s hard to know how generalizable this protocol is, but I’d say it’s worth experimenting with some sort of extended surge ~10 minutes before the end of your warm-up. If you’re doing a six-minute effort, it looks like you should aim just above your threshold. I know quite a few runners who have incorporated similar but shorter surges of ~1-2 minutes into their warm-up routine. There may be a good argument for runners to stick to shorter surges, since the impact of leg-pounding is a bigger factor than it is in cycling. In that case, you may be able to get away with a higher intensity. But so far I don’t think the research has answered that question — for now, it’s trial and error.

Running stride analysis of top marathoners at Boston

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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Just got around to reading Pete Larson’s very cool analysis of the strides of the top four men and top four women from this year’s now-legendary Boston Marathon, using high-speed (300 fps) video. He looks at a bunch of parameters, including footstrike and cadence. The “secret” to running 2:03 isn’t, unfortunately, revealed — but there are some very interesting nuggets. For example, Ryan Hall has the slowest cadence of the eight runners, at 174 steps per minute, while Desiree Davila has the fastest, at about 195. The post is definitely worth a read, as are Amby Burfoot’s thoughts on Pete’s data.

And analysis aside, the videos themselves are pretty neat to watch. Kudos to elvin314!

What’s the ideal running stride to avoid injury?

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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This week’s Jockology column in the Globe revisits a familiar question:

The question

Is there an ideal running stride, and can I learn it?

The answer

You may think running has more in common with day-to-day functions like breathing and eating than with more technical sports like golf or swimming: As kids, we learn how to run with no special instruction, just as our ancestors have for millennia. The result?

“Most people run very badly,” says Blaise Dubois, a Quebec City physiotherapist whose multi-day course on the prevention of running injuries has been drawing sellout crowds of health professionals, coaches and running enthusiasts around the world… [READ THE REST OF THE COLUMN]

I had a really interesting interview with Blaise Dubois for this article. We spoke for nearly 90 minutes — so of course, only a tiny fraction of the discussion made it into this article. Hopefully I’ll have time at some point in the next few weeks to go through my notes and write a blog post about some of the other things we talked about. Hat tip once again to this post from Pete Larson’s blog that convinced me to get in touch with Blaise.