Shoe industry insiders call it "the born to run effect."
In the three years since it was published, Christopher McDougall's Born to Run has single-handedly ignited the barefoot running craze. The bestseller argues that heavily cushioned shoes don't prevent injuries – they lead to them because they encourage a style of running in which people take large strides and land on their heels, sending impact forces shooting up their legs.
Running barefoot, by contrast, leads to a style of shorter strides and landing on the forefoot, which is the way humans were, yes, born to run, and supposedly minimizes injury.
That theory has launched the biggest trend in running. Groups of barefoot devotees have seen their ranks swell, shoe stores have opened that are dedicated to selling lighter footwear and more and more runners can be seen wearing them, including Patrick Sweeney, who won the Palos Verdes Marathon in a pair of Vibram FiveFingers in 2010.
Many runners who are wary of going barefoot still find the principle of Mr. McDougall's philosophy – less is better – very compelling. And shoe companies are seizing on the popularity of the book and the barefooting craze, pumping out a range of so-called "minimalist" shoes that are lighter and bring the heel closer to the ground.
"If you're a shoe company and you're not addressing this, I think you're crazy," says Mark Cucuzzella, a physician and owner of Two Rivers Treads, a minimalist running shoe store in West Virginia. Every major manufacturer, whether it's Nike, Saucony, Adidas, New Balance or Brooks, now offers minimalist running shoes. Many of them are marketed as shoes that runners could wear a few times a week while reserving their traditional shoes for other days or longer runs.
"Some people want to mix it up," says Richard Zartman, director of footwear design at Brooks, which introduced the PureProject, a collection of shoes that promote a natural stride, in Oct.
The athletic shoe market in Canada is worth approximately $1.3-billion, about 30 per cent of that going to running and jogging shoes. The U.S. running shoe market is worth approximately $6.5-billion. The minimalist category makes up about 15 per cent of that, according to Matt Powell, an analyst with SportsOneSource, which tracks retail sales data. Sales of minimalist shoes are up about double over last year, he says.
"We're seeing virtually every shoe now being offered in lighter weights than its previous counterpart was, and I think this is truly revolutionizing the shoe business," Mr. Powell says.
At Nike, which introduced the Free, a minimal trainer, in 2004, the "less is more" philosophy has spread beyond running shoes to other styles.
"As recently as four years ago, it was not uncommon for a basketball shoe to be 15 ounces. Sometimes we'd have 18-ounce basketball shoes. They were really like a big athletic boot. And because we realized that every player does not necessarily need all that protection … we started seeing shoes that would get down to 12 ounces, even 10.5 ounces. A couple of years ago, that would have been unheard of," says Scott Myers of Nike Canada.
Daniel Lieberman, a researcher at Harvard who has studied barefoot running, says the flood of minimalist running shoes is a sign of "the pendulum swinging back" from heavily cushioned shoes that has dominated the industry for decades.
In the 1970s, at the dawn of the running boom, the only shoes on the market were little more than racing flats. But as the sport grew in popularity, shoe companies began adding cushioning. The more padding there was in the heel, the more shoes could absorb impact forces, the thinking went. But the more the heel was lifted off the ground, the more technology had to be applied to the mid- and forefoot of the shoe. By the 1990s, shoe technology had become sophisticated enough to create a style for every kind of runner – stability shoes, neutral shoes and, the most cushioned of all, motion-control shoes.
"What's nice about this trend toward more minimal shoes is they're giving consumers more options," Prof. Lieberman says. Indeed, the choice has never been broader.
At one end of the spectrum is the Vibram FiveFingers Bikila, which features a heel-to-toe drop of zero millimetres and weighs a mere six ounces in the men's version. The lower the heel-to-toe drop of a shoe, the easier it is to land on your midfoot or forefoot.
At the other end is the Brooks Beast, a popular motion-control shoe that has a heel-to-toe drop of 12 mm and weighs 14 ounces. In between, there are many shoes, including the Nike Free and the New Balance Minimus that are positioned as transitional shoes for people looking to ease into barefooting. The Free 3.0, for instance, features a heel-to-toe drop of 4 mm and weighs 7.2 ounces.
This is the de-engineering of shoes, reducing or removing medial posts and plastic shanks and other technology in order to give runners a taste of what it's like to run barefoot. These shoes will feel remarkably light to anyone who's been lumbering around in traditional footwear, but don't let that tempt you into heading out on one of your regular runs.
Anyone who puts on a pair of minimal shoes for the first time and tries to do the same mileage they're used to is probably going to injure themselves, says Reed Ferber, director of the Running Injury Clinic at the University of Calgary.
"There's a camp here in Calgary, they have a shoe burning ceremony on a Friday, and they all book appointments on Monday," Prof. Ferber says. Any change of mechanics needs to be done slowly, he stresses.
The crucial point to recognize, experts say, is that shoes aren't going to magically transform your running. Even many minimalist shoe makers say they should be used as a complement to traditional running shoes, not a replacement. Runners might wear them on for their 5-km runs but revert to their old shoes for marathons, at least until they adjust to lighter shoes, the thinking goes.
Barefooting isn't really about what is – or is not – on your feet. Whatever you wear, the true benefits of barefooting come down to form and technique (see sidebar), Prof. Lieberman says.
"It's about you and your body. I think we spend way too much time and way too much effort and way too much attention has been paid to shoes," he says.
How to bare your soles
If you want to make the switch to barefoot running, or simply to learn the technique but still run in a pair of shoes, here's how to do it.
On your feet: Nothing. "If you really want to learn good technique, don't use any shoe, because you get all that feedback from your feet," Harvard researcher Daniel Lieberman says.
Where: "The best way to learn is to have somebody run barefoot on a smooth, hard surface. Not on a lawn, not on a beach," Prof. Lieberman says. Try your street (if it's paved) or a parking lot. "Because if it's the beach or a lawn, it's soft and you can do whatever you want. But if it's pavement, you quickly learn good form, because you get the feedback."
Key mechanics: Stay straight at the hips. "Leaning is verboten," he says. "And you should have a nice high cadence and land with short strides. Get up to 170, 180 steps a minute. Make sure you don't over-stride."
How much: Whether you're barefoot or in a minimal shoe, start by running no more than 1 km a week. From there, increase your distance by 10 per cent each week, says Prof. Ferber. "We really want people to reduce their mileage and build up very slowly," he says.
Timeline: Everyone is different, but give it time. "I don't think I've ever heard of anybody who's transitioned in less than three or four months," Prof. Lieberman says.