David Sypniewski started jogging in his early 20s, in an effort to lose weight and get in shape. Within a year he was plagued by injuries, including a bad case of runner's knee. He signed up for physiotherapy, had regular deep tissue massages and spent $400 on custom orthotics.
And then one day, he stepped out of his Calgary home and gingerly began to run in his bare feet, having discovered an on-line community that swears by the benefits of jogging without shoes.
"It felt absolutely fantastic," said Mr. Sypniewski , who is now 31 and living in Florida. "I actually started enjoying running. And I haven't looked back."
A new study by Harvard researchers has found that people like Mr. Sypniewski who run barefoot or in minimal footwear tend to avoid the heel-striking gait that causes so many running-related injuries.
"Most people today think barefoot running is dangerous and hurts, but actually you can run barefoot on the world's hardest surfaces without the slightest discomfort and pain," said the study's author Daniel Lieberman, a professor of human evolutionary biology.
His work, which appears this week in the journal Nature, is part of a growing body of evidence that suggests that fancy footwear is not the best way to reduce the impact of running.
Working with runners in the United States and Kenya, Dr. Lieberman studied the gaits of three types of runners: those who had always worn shoes, those who had always run barefoot, and a group that had converted to barefoot running.
He found that those who wore shoes hit their heel against the ground with dangerous force, while those who ran barefoot had a springy step and landed towards the middle or front of the foot.
"Barefoot runners have almost no impact collision," the study concludes. "It might be less injurious than the way some people run in shoes."
Dr. Lieberman believes that humans evolved to run millions of years ago, and that the arch and architecture of our feet is designed to absorb the impact of running, allowing our ancestors to run barefoot without hurting themselves.
The modern affection for $200 running shoes may actually have contributed to the prevalence of injuries by changing the way we run, causing people to come down on their heels instead of their toes.
"There is nothing wrong with shoes, and it's important to emphasize that one can fore-foot or mid-foot strike in shoes as well as barefoot," said Dr. Lieberman. He recommends running in shoes that do not have padded heels. "It's just easier to do so in shoes with less built-up heels, because one doesn't have to point one's toes as much."
Major shoe companies have already started to take note, incorporating the lessons of barefoot running into their design. New Balance shoes are designed to mimic the strike of barefoot running and Nike has developed a shoe called Free that has less cushioning. But some runners want even less on their feet. Many runners have begun wearing Vibram Five Fingers shoes, which resemble a rubber sock and separate each toe to replicate the feeling of a barefoot stride.
But not every runner is willing to ditch their cross-trainers just yet.
The idea of running barefoot is a major hurdle for many runners, who have been raised to believe that more cushioning reduces the risk of injury.
An ESPN poll last year found that only 34 per cent of respondents would consider running barefoot. Mr. Sypniewski, who runs the web site Barefootrunner.com, said many people still associate barefoot running with hippies, or a kind of extreme, developing world training regimen.
"I don't think we're going to see everyone in North America running barefoot in the next five years," he said. "At the end of the day we do need some foot protection."
Dr. Lieberman cautioned that a transition to barefoot running should be done gradually. Runners should not increase the distance they run by more than 10 per cent a week, he said, and should stop and seek medical advice if they experience any pain.
"My big worry is that the biggest challenge of barefoot running is that it requires a lot more calf muscle strength and Achilles tendon stretching and people can be prone to Achilles tendonitis if they don't transition gradually and carefully," he said. "It's not for everyone."