Take your shoes off. Run a spell.
That's the advice from a multinational study on running that's the cover story in the February edition of the scientific journal Nature.
Barefoot runners, who tend to land midfoot or on the balls of their feet, put much less stress on their bodies than do the well-shod, whose athletic shoes encourage 75 percent of them to be "heel-landers," say researchers at Harvard, Providence Veterans Affairs Medical Center, the University of Delaware and Moi University in Kenya.
Barefoot runners also are faster and less prone to injury, according to Daniel Lieberman, a Harvard professor of human evolutionary biology and a co-author of the study on runners in the United States and Kenya.
Lieberman, and others interviewed for this story, stress that any conversion to barefoot running or the gait known as "forefoot striking" should be done gradually. The joints and muscles that will support your new gait aren't ready for a marathon.
"The big fear many of us have is what happens when you translate the science into the popular press - that people are just going to take off their shoes and run barefoot for six miles," said David Raichlen, an assistant professor of anthropology at the University of Arizona, who was not part of the study but was familiar with the report and Lieberman's research.
"Start slowly," Raichlen said. "The muscles and ligaments in your feet are not as strong as they need to be."
Barefoot running already is a big fad, said Tucson runner, coach and race organizer Randy Accetta, and not one he recommends. Accetta enjoys running barefoot, but only on grass for short periods of time. For longer runs, he always straps on running shoes.
He doesn't disagree with the study's premise that heel-striking causes the intense jolts that lead to foot problems, but said most runners can avoid that by simply shortening their strides.
He also worries about the surfaces he runs on. "I don't think you are going to get me to go on a barefoot run up Sabino Canyon on the Phoneline Trail."
Local runner Craig Dabler said his recent experiment in barefoot running produced immediate relief from back and foot pain. He had read in the book "Born to Run" by Christopher McDougall that over-engineered running shoes were the cause of many physiological problems.
Dabler, a local jeweler, said he started slowly, taking his shoes off at the end of a regular run to walk on pavement and rough up his soles. "I think the neighbors were ready to commit me."
He began running barefoot on sidewalks. "I never felt better running than when I was barefoot," he said.
Then he broke his foot.
Dabler was barefoot when he dismantled his daughter's bunk bed early this month. He dropped a 4-by-4 piece of lumber on his foot.
He was running a few days later when the fracture occurred. He's convinced it was the board, not the running, that did it.
Tucsonan Jay Ferrell said he began running barefoot to see if it would help joint pain, particularly in his knee.
It did, he said. It was awkward at first, but he came to like it. "I was actually feeling what was happening with my foot. I met muscles I didn't know existed."
He began to feel he was simply "skimming the surface of the ground." He ran up to 10 miles at a time on dirt trails in Sabino Canyon and Saguaro National Park.
He stopped only because "life intruded" and he began running less. If you don't keep it up, your shoe-pampered feet lose their toughness.
Lucas Tyler, manager at The Running Shop, said he's always sold a lot of lighter, thinner racing shoes. But the trend toward minimal shoes, such as the Vibram Fivefingers product he sells, accelerated last year with publication of "Born to Run."
The book chronicles the distance runners of the Tarahumara tribe in northern Mexico, who wear rudimentary sandals fashioned from tires. It includes discussions of Lieberman's earlier studies on running.
For scientists such as Lieberman and Raichlen, barefoot running is part of greater research into the evolution of mankind.
They theorize that our running physiology was developed to give us the endurance needed to outlast speedier prey. We were, indeed, born to run.
"In the evolution of locomotion, endurance running began about 1.8 million years ago. There were no shoes," Raichlen said. "We evolved to run barefoot."
E-mail Q&A with Daniel Lieberman
Are you a runner?
Yes, I love to run and have run regularly since I was a teenager. I'm not a very good runner in terms of speed, but I do about 20 to 30 miles a week and have run two marathons so far.
Have you run barefoot?
After studying runners in Kenya, I just had to try going totally barefoot. I was finishing a long run and found myself taking my shoes off about a half mile before I got home. Even though I knew all about how it worked, I was amazed at how fun, comfortable and good it felt. Since then I started running more and more barefoot. And then winter hit. Humans evolved to run barefoot, but not in New England winters!
What's wrong with landing on your heels?
First, when you land on your heel, the foot and lower leg come to a sudden stop as the rest of the body continues to fall. But when you land toward the front of the foot, only the foot stops, and the rest of the leg continues to rotate. In addition, forefoot strikers have much more springy legs, which spreads the impulse out over a longer period of time. It's like jumping off a chair and landing on your heel with a straight leg or landing on the ball of your foot with a springy leg.
The world's fastest runners all forefoot strike. And many of the world's very best marathoners don't heel strike.
What's wrong with the way most people run?
Heel striking generates a big, rapid collision force about 1.5 to three times your body weight. It's like someone hitting you hard on the heel with a hammer with 250-500 pounds of force with every step.
What about stubbed toes?
I've run hundreds of miles barefoot, and have yet to land on my toes. One lands on the ball of the foot.
I live in Tucson, Arizona. Is there a special caution for very hot places with cacti?
Ouch! Our article is NOT advocating that we go barefoot. Simple footwear such as sandals and moccasins have been around for thousands and thousands of years. And for good reason, especially in places with cactus spines.
Vibram USA, which makes minimalist running shoes, is listed as a sponsor of your research. What is the extent of its support?
Vibram USA paid for a research assistant and gave free shoes to some of our volunteers, but they have no special rights or access to any of the data, no input into our experiments, and no control over how and what we publish. Further, they have not paid me a penny, and I don't own any stock or profit in any way from this research.
Contact reporter Tom Beal at 573-4158 or email@example.com