This article originally appeared in Shape.

Could your bad shoes be the cause of injuries?

"Many injuries of the feet and ankles can be traced back to ill-fitting shoes," says Megan Leahy, D.P.M., a podiatrist at the Illinois Bone & Joint Institute in Chicago, Illinois. But with thousands of model options—all of which change in form and functionality more frequently than T. Swift releases a hit single—how do you know if you're wearing bad shoes? Read this before sole searching.