The symptoms are distinct: a popping sound followed by a pain that makes you think you were shot in the back of the ankle. If it happens to you, you probably have an Achilles tendon rupture. "People just doing everyday activities can end up with a ruptured tendon," says Brian Donley, M.D., vice chairman of Cleveland Clinics Department of Orthopaedic Surgery and director of its Orthopaedic Foot and Ankle Fellowship. A ruptured Achilles tendon is a serious problem that can keep you from walking properly-or at all. And while a tear in your tendon can be repaired, youll save yourself a lot of pain and temporary disability if you try to prevent the injury in the first place.