Thank you, Steven Sashen, founder of Invisible Shoes, for providing much-needed clarity on a topic that is as polarizing as health care legislation, or whether Mad Men is a better television show than Breaking Bad. Last week, New York Times health and fitness reporter Gretchen Reynolds wrote about a new barefoot vs. shod running study on the Times Well Blog. The title of her article: Making the Case for Running Shoes.
Any time, you mention these two words– “barefoot” and “running” in the same article, the knives come out, with the shoe set positioned on one side, the barefoot bunch on the other. It’s like Braveheart without Mel’s blue stripes. The study has made international news and clucking sounds from self-appointed Anti-Barefoot Told Ya So’s, including this one from the Times of India, whose headline reads, “Barefoot Running may be Less Efficient,” followed by this info-deck: ”A new study has raised doubts over the minimalist running shoe movement, which may have prompted people to ditch their running shoes.” (Call me cynical, but I wonder how many people in India go barefoot or wear flat sandals and the number of podiatrists and sports injury clinics there.)
Here’s Steven’s take (it originally appeared on Invisible Shoes) on the headlines-grabbing study that involved only 12 runners. or less than .ooooo6 percent of the running population in the U.S, yet the “data” has been extrapolated and recklessly disseminated by the media so that it has now begun to mainstream-morph into incontrovertible evidence that barefoot is less efficient than running in shoes. But “facts” can be awfully deceiving. Ask any magician or politician or some German physicist named Werner Heisenberg. — Bill Katovsky
University of Colorado Barefoot Running Study Debunked
by Steven Sashen
Each of the dozens of articles about the study has a distinct flavor of elementary school playground taunting, “Nah, nah, nah, nah, boo, boo… barefoot running isn’t good for you!”
I mean, check out some of the headlines:
Debunking the Barefoot Running Myth – Sydney Morning Herald (barefoot running isn’t like bigfoot!)
Here’s Proof Barefoot Isn’t Better — Running Times (Ha! So there!)
It almost feels like the press is enjoying creating a backlash to all the “pro” barefoot articles of the last two years, even though in every barefoot article I’ve read the media insists on publishing “both sides of the story,” and includes some doctor who’s never run a meter in bare feet and wouldn’t know decent barefoot running form if it ran him over, claiming that running without shoes will hurt you, bring shame on your family, and accelerate the coming apocalypse.
So, let’s take a deep belly breath or two and have a chat about the study. In fact, let’s start by talking about studies, in general:
Designing a biomechanics study is not easy. Aside from deciding exactly what you want to explore and the best design of the study itself (how you can test it), finding enough of the right kind of participants is often tricky, if not impossible.
It’s even more difficult to design a study that isn’t artificial in some way. That is, it’s showing effects in a lab that may not be relevant in the real world.
And, even more, many studies, while interesting, may not be relevant to the broader population. (Whenever someone quotes a study, or even just the habits, of elite marathoners, I respond “Unless you’re 5’5″ and weigh 105 pounds and run at 13 miles per hour for two hours… who cares what those guys do?)
Finally, the way the media picks up a study — this one or any of the previous barefoot studies — often adds some spin that isn’t in the actual study.
All of the issues I just raised are relevant as we take a gander at the CU study. By the way, if you want to see a lively and cogent critical look at the study, you can’t go wrong with reading the comments on the New York Times article about it. Frankly, this post probably won’t be as lucid as some of the comments there.
Okay, let’s jump into it… The gist of the study:
“In the study, 12 subjects with substantial barefoot running experience ran at 7.5 MPH with a mid-foot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (~150 g/shoe, 5.4 oz). In additional trials, they attached small lead strips to each foot/shoe (~150, ~300, ~450 g). For each condition, they measured the subjects’ rates of oxygen consumption and carbon dioxide production as an index of metabolic cost.”
And the results:
a) For every 100g (3.5oz) (the average weight of a deck of playing cards) added per foot, energy cost increases by approximately 1% whether running barefoot or shod.
b) Running barefoot and in lightweight shoes do not significantly differ in energy cost.
c) When controlling for shoe/foot mass, running in lightweight shoes requires ~3-4% less energy than running barefoot.”
Now, let the fun begin. Can you find the “confounds” (the factors in the study that might affect the results, or the interpretation of the results)?
I’ll start. Let me know if you find more.
1) How did they determine that the 12 subjects had “substantial barefoot experience?” Well, the study says, “8 km/week barefoot or in minimal running footwear (e.g. Vibram FiveFingers) for at least 3 months out of the last year.”
Does 3 months out of the last 12 really equal “substantial?” I’ve been barefoot for 3 years, and I’m STILL improving my form.
And if that three months was wearing VFFs or minimalist shoes, that counts as “barefoot experience” Uh…
Now the researchers did verify that the subjects all ran with a “midfoot or forefoot” landing. I know that Lee Saxby, the spokesman and coach from Vivobarefoot would have an issue with that. He doesn’t think midfoot is proper barefoot form (there’s some debate about that, but it’s besides the point at the moment).
2) They ran on a treadmill. Look, I get that testing runners on an actual track is hard and expensive, but running on a treadmill is not the same as running on the ground, end of story. It may give some useful data, but if it walks like a duck and quacks like a duck, but the duck is on a treadmill… hmmm, that analogy isn’t quite working, but you know what I mean.
I did some high-speed video analysis of my running at the Monfort Human Performance Lab. I hit 21 mph on that treadmill. I can tell you that when I’m on a treadmill, my stride is different than on the track. I overstride so I can “catch” the treadmill belt, for example.
3) To simulate a running shoe’s weight, the researchers put lead weights on the top surface of the runners’ feet. Do you think some small weights pressing down on your foot is different than having that same amount of weight distributed evenly, and mostly under your foot, thanks to the design of the shoe? I do. Does that matter? Could be. Is there a way to check… not easily.
4) The runners were at 7.5 miles per hour. That’s slow for an elite runner – about 200 meters in a minute, a quarter mile in 2 minutes, a mile in 8 minutes — but fast for most casual runners. This raises a few questions:
a) How was that pace compared to the runners’ usual training pace?
b) Does speed make a difference?
c) What about turnover, or cadence? Were those controlled and the same when the runners were barefoot vs. shod?
Got me. But, suffice it to say, we’re seeing the artificial quality of the study.
5) Oh, this wasn’t mentioned above, but I’ll give it to you now: the runners were wearing yoga socks. ““For the duration of the experiment, subjects wore very thin, slip-resistant yoga socks for safety and hygienic purposes.”
Hygienic purposes? Uh, some 409 and a paper towel would handle any “hygiene issues.” And “safety”? If you read the study, one aspect of “safety” is “avoiding blisters.”
Boy, where to start on that one? We know that socks does not equal barefoot, and we also know that if you get blisters when you run barefoot, you’re doing something wrong. So, this brings us back to number 1 — how experienced were these runners really?
6) The study measured oxygen consumption and carbon dioxide production. Okay, that’s a fine way to measure efficiency, based on the idea that using less oxygen and producing less CO2 means you’re using less effort, and that equals being more efficient.
But here’s a question: So what?
For one: does using less energy equate to faster times? It seems like it might, but that’s not a given.
Does the amount of extra energy being used by *some* of the barefoot runners have any relevance to the average runner? Someone for whom 7.5 mph is too fast… or even too slow?
7) Oh, here’s a favorite. The runners in the study wore an ultra-lighweight racing flat. Most runners wouldn’t wear those. And most runners with no barefoot experience wouldn’t find those any friendlier than being shoe-free.
Don’t get me wrong, I’m thrilled that my Boulder neighbors are researching barefoot running. And while this is the first published study, I know they have more coming and I’m looking forward to those.
And I’m certainly not blaming them for how the media is handling the story.
My only interest is the continued exploration, conversation, and understanding of efficient movement, running for speed and/or distance, and the ways of teaching and exploring barefoot running (and walking and hiking).
No one study can perfectly address all of the open questions. But the almost combative attitude where everyone wants to jump on some one-sided “We’re better!” bandwagon certainly doesn’t help.
Now, if you’ll pardon me, I have to burn off some of my frustration by putting on some yoga socks and minimalist shoes and going for a barefoot run.