Shoed runners also can run toward the front or middle of the foot, and he said that there are trade-offs that accompany all styles of running.
While front-strike running might be collision-free and require less energy to run the same distances, it requires more calf and foot strength and more stretching of the Achilles tendon.
Lieberman personally enjoys running in minimalist shoes that make for a barefoot-like experience but said he isn't trying to overthrow the shoed majority.
"This is not about barefoot versus non-barefoot. It's about strike style," he said, adding that whichever style people choose, they need to be careful.
"About a third of runners get injured," he said. "What we need to do is try to figure out how different styles of running cause people to be injured."
Still, for those runners who choose to go shoe-free (or come as close to the experience as possible), Lieberman's study indicated that barefoot running is a trend with growing support.
"Its got a lot of gravitas. ... It is a radical paradigm shift," said "Barefoot" Ted McDonald, a long-distance barefoot runner and coach whose experience is featured in the best-selling book by Christopher McDougall, "Born to Run."
In addition to coaching and speaking about barefoot running, McDonald maintains a Google group called "Minimalist Runners" that includes more than 1,000 members.
About five years ago, he estimated tens of thousands of people would count themselves among barefoot or minimalist runners. Now, he said that number is in the hundreds of thousands.
"I think [barefoot running] has been eccentric in our generation from the get-go. ... You're like a smoker, you're willing to take a huge risk," he said. But now, "we're reaching the tipping point. ... It's a trend that won't be going away anytime soon."
Companies such as Vibram, Terra Plana and Feelmax have started to cater to the minimalist crowd with thin-soled shoes that are conducive to a front- or mid-foot strike gait. The Nike Free also offers a similar experience.
In December, a study by the American Academy of Physical Medicine and Rehabilitation suggested that running shoes could increase pressure on joints compared to barefoot running.
"Once you take off your shoe, you no longer pound the ground," said McDonald. "My way of approaching it is getting people to run more like dancers move across the stage -- with form and grace and strength."
Though he runs with a minimalist shoe on occasion, whenever he can he goes completely sans sole. Like Paisner, he said that barefoot runners' feet become tougher and stronger and adapt to handle direct contact with the open road. Both say they've never experienced any major cuts or bruises from running barefoot.
But the barefoot movement is not without its detractors.
In an e-mail to about 3 million subscribers, Michael Gotfredson, founder and "chief runner" of Road Runner Sports, a retailer of running shoes based in San Diego, Calif. that says it's the "world's largest running store," issued a "warning about barefoot running."
"Don't follow blindly the latest trend. The barefoot running thing is an injury waiting to happen," he wrote. "Ever walked on the beach or a sidewalk and seen shards by the dozens? Don't step on those if you plan on running in your future."