This article originally appeared in Well+Good.

Arm day, leg day… foot day? When you’re working up a sweat, your feet likely get less attention than larger muscle groups (we’re looking at you, core workouts!), but when you have flat feet—which, according to some estimates, as much as 30 percent of people do—targeted flat feet exercises are crucial for preventing injury and pain.

Flat feet, also called fallen arches or pes planus, have little to no arch. “The arch of the foot collapses, and the sole of the foot comes into full or almost-full contact with the ground [when standing],” says Suzanne Fuchs, DPM, a podiatric foot and ankle surgeon.