What kinds of problems result from too much pronation or supination?
The problems secondary to bad foot mechanics can be far reaching, from the feet all the way the spine and to the neck and shoulders.
During pronation, the arch partially collapses and the foot remains “unlocked”. This elongates the foot (your arch is longer when standing than sitting) and can stretch the ligaments and muscles on the bottom of the foot, causing pain often referred to as plantar fascitis. If this goes on long enough, you can actually develop a heel spur. The abnormal pull of the muscles on the feet can cause bunions, claw, and hammer toes.
The lower leg rotates inward (medially) when the foot pronates. If this happens excessively, it can cause damage to the knee resulting in pain in the knee or kneecap.
If the lower leg rotates inward, the hip follows it. In excess, this can cause hip and low back problems. Because the spine is a series of curves and compensations for what happens after the foot comes in contact with the ground, problems can occur in the mid back, neck and shoulders as well.