Wearing high heels for long periods of time. Over the years, the Achilles tendon in the back of the calf shortens and tightens, limiting the bending motion of the ankle joint. The tendons and ligaments running through the arch then try to compensate. Sometimes they break down and the arch falls.Some studies have indicated that the earlier one starts wearing shoes, particularly for long periods of the day, the higher the risk for flat feet later on.