Most people with flat feet have a condition that is referred to as a flexible flat foot. This is caused by excessive flexibility within the joints and ligaments of their foot and is often hereditary. This results in an over pronated (rolled in) position and is exaggerated by mechanical misalignment of the foot. This can be a very destructive position for the foot to function in and can cause a wide variety of foot, leg and lower back conditions.

The appearance of flat feet may vary from foot to foot. Generally there is a collapse of the medial (inside/middle) long arch of the foot. This may occur mildly where the arch height drops slightly or can be a large movement that results in the entire length of the arch resting on the ground. The twisting and misalignment of the foot that occurs with arch collapse can cause excessive wear and tear of the foot joints and eventually pain. Flat feet can lead to a number of foot and lower limb symptoms. This is largely due to the inefficient position the foot is placed in when it over pronates (rolls in).