As a result, it pays to do a little homework before you buy.
Pronation is a slight inward rolling from the outside back of the heel to the inside forefoot.
It happens naturally when you run. As pronation occurs, your feet flatten, which helps them absorb a force of up to two and a half times your weight. If your feet pronate a lot, there's a risk of joint injuries, muscle strain, and back pain. Running shoes are designed for different degrees of pronation. You'll increase your chances of buying the right shoe if you assess the motion of your feet before you shop.