Patients may be told by running shops or medical practitioners that they abnormally pronate but what does this actually mean? Put simply, the foot has the ability to change from a more mobile structure to a more rigid one and visa versa. This change is desirable so that the foot can adapt to terrain but become stiffer during push off. The mobile phase is associated with pronation and the more rigid phase with supination. The London Podiatry Centre uses 3D Vicon technology to accurately track the joints of the foot so that a true measure of relative pronation and supination can be calculated. For example the height of the first metatarsal which makes up a major part of the arch is measured dynamically. Motion of the ankle and back of the foot is also measured and it is a combination of these measurements which allows us to accurately determine whether foot motion is normal. If it is not then treatment is initiated.