Several years ago, during a grateful stretch of employment after the birth of my first child, I got an assignment from a glossy and hip national magazine to review trail running shoes. I had reviewed cologne and grooming supplies, but had never before reviewed high-end sports footwear.

I was promptly shipped more a dozen pairs of high-performance shoes, really gorgeous stuff, the very best brands, retailing $60 to $120 a pair. My closet was suddenly ridiculous, and I took the job very seriously, lacing up every pair and heading out to test the shoes through snow and rain and mud.

Eventually I picked out a best of the batch, and did my best to justify the call in print, but when it was all said and done I had a hard time knowing why. I think I chose one shoe over another because of the way the shoe performed, but I may have also really liked the way it looked. Part of me wondered if the whole thing wasn’t a bunch of b.s.

Maybe I wasn't cut out for shoe reviewing (they never called again). Then again, maybe I was right. A revolt over whether we should wear running shoes has taken on momentum lately. It first began in the late 1980s, when a study found that the more your shoes cost, the higher the injury rate. That could mean a lot of things, of course -- maybe people who pay more for their running shoes run more aggressively, and thus get injured more, for example. But another study published during that time suggested barefoot runners get injured less because their arches adapted to better deflect impact forces.

A lack of evidence
Lately, nothing less than the great running-shoe value system has come under question. You know that advice you get in the shoe store -- that to prevent injury, people whose feet turn from side to side, or pronate, should wear "stabilizing" shoes, while everyone else should wear "cushioning" shoes? It turns out no one has ever proven that notion, according to a survey of the literature recently published in the British Journal of Sports Medicine.

That study was highlighted in a recent article in the New York Times on the phenomenon of shoeless running, a trend that has given rise to shoes (such as Vibram FiveFingers) specifically designed for shoeless runners. (What’s next, guitars for playing air-guitar? Umm, skip that ... .) "Born to Run," a new book by magazine writer and runner Christopher McDougall, examines the question in even greater depth.

The proponents of shoeless running argue that it helps protect injuries to the foot, lower leg and ankle, but given that the entire leg from the foot through the hip is a linked system, I’m hoping it won’t be long until they discover that shoeless running has benefits for the region home to the most vexing of running injuries, the knee.

Irene Davis, PhD, a researcher at the University of Delaware, past president of the American Society of Biomechanics, and newly converted barefoot runner, has measured impact forces with and without running shoes.  Though anecdotal observations are many, she says, "unfortunately there’s not a lot of concrete evidence that suggests that when you run barefoot you get injured less."

A question of landings
Davis says it's possible that barefoot running is smarter, however, and the issue comes down to the biomechanics of how runners land. Most runners (80 percent) run with a rear-foot strike pattern, landing on their heels and rolling through to push off from the balls of their feet. She says running shoes cushion the heels during this pattern, "but you have a quick rise to impact peak" running heel-first. In runners with a forefoot or mid-foot strike pattern, on the other hand, "[their] peak becomes attenuated," Davis says. We all have a pattern we are born with, but necessity requires barefoot runners to change to a mid-foot pattern. "When you barefoot run you can’t land on your heel," she says. "It hurts. Go out and try it."

Davis doesn’t know whether barefoot running will protect the knees, but says it would appear to reduce the forces on the tibia, and "that’s probably going to be good for the knee." Diabetics and people with arthritic conditions need to keep their running shoes on, she says. Others can take off their shoes, but need to start small. "I did it slowly," she says. "I started at a quarter of a mile, then moved it up to a third of a mile, and then a half a mile."

'A natural pumice stone'
She says her feet have actually become softer in the process. "I’m a girl," she says, "so my worry was I didn’t want calluses. The pavement serves as a natural pumice stone."

Ironically, grass is more dangerous for shoeless runners than paved paths. "The problem with grass is you don’t know what’s underneath it." Pavement resembles hard-packed natural running surfaces in places like Copper Canyon, Mexico. More important, pavement is hard, and in terms of biomechanical re-education a hard surface is the whole point of taking the pillows off your feet in the first place. Hard surfaces force you to land even smarter than you would on grass. "When you run on pavement you’ve got to cushion more." With your body.

Freelancer Paul Scott, of Rochester, writes frequently about health and fitness for various media. Susan Perry is on vacation.