There are a variety of potential causes of pronation. The condition is often the result of a hereditary defect that causes the ligaments and muscles supporting the joint to be loose. It also can be caused by regularly wearing unsupportive or damaging footwear such as high heels, tight muscles surrounding the joint, and internal rotation of the leg.
Pronation, a condition in which the foot and ankle roll inward when running or walking, is a normal and natural part of a human’s gait. The problems start when the foot pronates too much, something known as excessive pronation or overpronation. When this occurs, the foot and lower limb moves inward too much, causing the rest of the body to compensate. Over time, this increases the chances of overuse and repetitive strain injuries.
Although there are several potential causes of pronation, the most common is a hereditary defect. If a person is born with loose tissues in the ankle and foot, then the bones are not tightly held in place. This allows the foot to turn inward more than it should while walking. As the person continues to grow, the bones, ligaments and muscles all develop to compensate for this defect. Over time, the looseness of the tissue tends to become worse.
Other potential causes of pronation are less common but still important. Women who regularly wear high heels, for example, are thought to be more susceptible to overpronation. This is because the high heels place the foot in an abnormal position that can result in laxity of the surrounding tissue.
Older people also are more likely to suffer from overpronation. This is because the muscles supporting the ankle joint naturally become weaker as people get older. The result is a collapsed foot arch, which can contribute to excessive overpronation.
There are a number of other potential causes of pronation. If the muscles and tendons at the back of the lower limb — such as the calf muscles and Achilles tendon — are tight, then the foot and ankle may be forced to pronate to compensate. If the femur — the thigh bone that starts at the hip — is internally rotated, then this also can cause the foot to pronate. In most cases, the only way to determine the underlying causes of pronation is through a full-gait analysis, which usually involves recording equipment so the motion can be slowed down and analyzed.