About 25 percent of the population has a condition called flat foot, a collapse in the arch of the foot. It can cause pain in the ankle, heel or leg and eventually the knees, hips, and back. But now ...

When I was a kid, my pediatrician was very concerned that my overpronated gait meant that I was on my way to having my father’s flat feet. My parents, determined to derail this, enrolled me in ballet ...