There are a number of tendons in the foot which helps control movement whilst walking and running. The two major tendons which go around the outside of the ankle are called the peroneal tendons. These tendons help to control movement and prevent lateral (inversion) ankle sprains. Overuse and injury of these tendons causes dysfunction and weakness. Normally, these tendons pass behind the bone on the outside of the ankle (fibula). In some instances, injury can cause the natural restraining mechanism to fail and allow the tendons to slip over the bone (Peroneal tendon dislocation).