The windlass mechanism is a very important part of foot biomechanics and is the body’s natural way of supporting itself. Failure of this mechanism results in a number of complications and symptoms.
The windlass consists of the plantar aponeurosis or plantar fascia which is a strong ligament that attaches to the bottom of the heel and to the base of the toes. As it attached to the toes, when the toe is bent upwards, the arch of the foot is raised. This is what happens when the heel lifts off the ground when walking or running and is the reason that the arch come up after the heel starts to lift from the ground.
A number of things, such as hallux rigidus or functional hallux limitus can cause the windlass mechanism to fail. There are also problems with a delayed onset to the windlass mechanism and also a high force needed to establish the mechanism.
One of the goals of foot orthotic therapy is to facilitate the windlass mechanism. Various design features (eg Cluffy Wedge) are added to foot orthoses to achieve this. Some inappropriately designed foot orthotics can actually inhibit this mechanism.