Shoes that raise the toes make walking easier, according to a small study. The downside is that this might weaken the foot, increasing the risk of a common and painful condition known as plantar fasciitis.

When Freddy Sichting at the Chemnitz University of Technology in Germany went running with Daniel Lieberman of Harvard University – whose work helped popularise barefoot running – the pair started talking about how shoes affect feet. In particular, they wondered about the way the sole of most shoes curves upwards under the toes, …