How you're built, how you run, and how well you recover all affect your training load.
Studies suggest it's actually good for you.
A British newspaper hired biomechanics experts to study his recent changes.
Many fitness instructors have made the switch.
The editor of Canadian Running raises some doubts.
One researcher thinks so.
One runner taking part in this weekend's Boilermaker Road Race thinks so; a foot and ankle surgeon doesn't.
He is the co-founder of the Barefoot Running Club in Boulder, Colorado.
He will be traveling to 13 cities.
One professor suggests running a couple half marathons before the big race.