Monday, July 21, 2014

Minimalist Sneakers Can Cause Injuries, Too

English: Vibram FiveFingers Bikila shoes, top ...
English: Vibram FiveFingers Bikila shoes, top view. (Photo credit: Wikipedia)

by Gretchen Reynolds

When Dr. Douglas Brown, a radiologist in Orem, Utah, noticed an uptick recently in the number of barefoot runners he was seeing with heel and foot problems, he wondered if there might be a connection between their unshod training and their sore feet. But he couldn't find any scientific studies that had examined the issue.

So he approached Sarah Ridge, a professor of exercise science at Brigham Young University in Provo, Utah, who studies impact injuries in sports, and suggested she undertake one.

The resulting study, published in Medicine & Science in Sports & Exercise, will probably add fuel to the debate about the benefits of running barefoot or wearing minimalist "barefoot" shoes. Does the barefoot style reduce a runner's risk of pain and injury (as enthusiasts believe)? Or does barefoot running simply contribute to the development of a different set of injuries in some runners?

To find out, Dr. Ridge began by recruiting 36 experienced runners, men and women, who, until then, had run between 25 and 50 kilometers a week while wearing normal running shoes. She sent them to Dr. Brown for baseline M.R.I. scans of their feet and lower legs to check for any injuries or problems.

Those who believe in barefoot running often point out that humans ran and walked without shoes for millenniums before footwear was invented. They argue that being unshod is normal for humans and should reverse past injuries related to modern running shoes and prevent future ones.

But anecdotal evidence from physicians who treat runners indicates that some people who take up barefoot running develop entirely new aches and injuries.

Dr. Ridge's volunteers all started the study with normal feet and lower legs, according to their M.R.I. scans, which were read by multiple radiologists.

Half of the group members were randomly assigned to continue running as they had: same distance, same shoes.

The other runners were given a pair of Vibram Five Fingers barefoot-style shoes and asked to increasingly incorporate some barefoot-like distance distance into their runs, but gradually.

After 10 weeks, both groups of runners received a follow-up M.R.I. There was no evidence of injuries to or changes in the tissues of the lower leg, like the Achilles's tendon, in any of the runners. But more than half of the runners wearing the minimalist shoes now showed early signs of bone injuries in their feet.

Natural way to repair bone damage?

Most had developed bone marrow edema, an accumulation of fluid, similar to what happens during bruising, in their foot bones. Two even had full stress fractures, one in her heel bone and one in his metatarsal, one of the long foot bones.

Almost all of the runners in the minimalist shoe group were spontaneously running fewer kilometers at the end of the 10 weeks than they had been at the start, "probably," Dr. Ridge said, "because their feet hurt."

Why some of the barefoot-style runners developed serious foot problems and others did not is not yet clear, but Dr. Ridge is now analyzing additional data about the volunteers, which includes information about each runner's mileage, running form, body weight and other variables.

"What we hope to see is whether there are some runners who, because of their biomechanics or other factors" seem to be particularly predisposed to foot injuries during the transition to barefoot-style running and perhaps shouldn't make the switch at all from normal running shoes, she said.

The results don't mean that everyone who chooses to switch to minimal or no footwear will court foot injury, Dr. Ridge said. "But I would tell anyone who wants to try" kicking off their normal shoes, "to be extremely cautious during the transition period." Increase your use of minimal wear slowly.

Barefoot-style running may have been natural for our ancestors, Dr. Ridge points out, but it's a new experience for most of our feet.

Taken from TODAY Saturday Edition, April 13, 2013