(AP) -- As more people experiment with barefoot running, foot doctors say they are treating injuries ranging from pulled calf muscles to tendinitis to stress fractures.
Problems can occur when people transition too quickly and don't allow their body to get used to the different forces when running without shoes or in "barefoot running shoes."
Runners who use shoes tend to have a longer stride and land on their heel. Barefoot runners have a shorter stride and land on the midfoot or forefoot.
Many converts are inspired by the book "Born to Run" and believe they are less prone to getting hurt if they ditch their sneakers.
Research is ongoing to figure out whether barefoot running actually reduces injuries. Scientists also want to learn what types of runners will benefit most from switching over.