There are a number of tendons in the foot which helps control movement whilst walking and running. One of the major tendons, the tibialis posterior tendon, arises from a muscle in the back of the leg, passes around the inside of the ankle and inserts into the majority of the bones in the heel and midfoot. This muscle and tendon helps a slow lowering of the arch (pronation) during walking and running. Overuse and injury of the tendon causes functional abnormalities hence the term tibialis posterior tendon dysfunction.