NEW YORK (CBS 2) –  City sidewalks in the summer can be hot, crowded and covered with grime. Most people don’t want their shoes to touch the stuff on the streets — never mind their bare feet.

But that’s not the case for the Barefoot Runners of New York City. The group is getting ready to run from Harlem to Brooklyn without sneakers.

“We all started out barefoot, we call them birthday shoes,” John Durant of Manhattan told CBS 2′s Kathryn Brown.

Running barefoot is nothing new, but many say thanks to Christopher McDougall it’s making a huge come back.

McDougall — an avid runner and author — traveled the world to learn the secrets of some of the world’s greatest long distance runners.

The key to their success, McDougall said, is that few of them wear shoes.

“Up to 80 percent of all runners are injured every year and that’s what lead me on this expedition,” McDougall said.

Running barefoot forces people to run the right way instead of running heel to toe like when wearing shoes. When barefoot, individuals land on the soft mid part of the foot and take shorter strides.  That, theoretically, puts less stress on joints preventing one from getting injured, Brown reports.

“It’s when we try to out think nature and stick all this junk in our shoes that’s what causes problems,” McDougall said.

“I had a lot of injuries before I started barefoot running, shin splints, I had stress fractures,” Melissa Bybee said.

How a person stands, moves and lands on their feet is completely different than they would in shoes. There is also another factor involved — all the things a person could potentially step on.

“I’ve run through some great stuff you know — pidgeon poop,” Bybee said.

McDougall said you quickly learn to side-step debris and that the more you run, the stronger the soles of your feet become.

Barefoot running, however, is not without its critics, including podiatrist Dr. Christopher Ferguson.

“I’m not against running barefoot but I definitely know it’s not for everybody,” Ferguson said.

Ferguson said it’s a misconception that barefoot runners are less susceptible to injuries like stress fractures.

“It touts all these kinds of benefits that you can have. The problem is the literature, the studies don’t really support what they’re claiming happens.”

But one thing it may do is burn more calories because some studies show more of your body gets worked out, Brown reports.