The windlass is that equipment which are used by the mariners on yachts to wind the rope around in order to make it less difficult to move the sails. Within the foot there exists a mechanism that is known as the windlass mechanism that gets its name from this apparatus used on boats. There is a ligament like structure under the foot called the plantar fascia which is at one end attached to the bottom of the heel bone and at the other end to the great toe. When we are walking and the rearfoot comes off the floor, the foot moves around the great toe where this ligament is connected, tightening up the plantar fascia as it winds around the windlass of the first metatarsal bone. This is the windlass mechanism of the foot. It is a significant functionality as that ligament is the thing that supports the arch of the foot, so it really should function correctly and quickly for normal function. It is the foots natural arch support system.
There are a number of conditions related to this windlass mechanism not functioning adequately. In the event the windlass mechanism doesn't work, then the arch of the foot will collapse from the lack of support and a range of disorders can develop as a result of that for example bunions and heel pain. The reason for the windlass not functioning correctly can be multiple such as the force required to establish it just being too high, so the body needs to work harder to help make the windlass function. If that effort does make it work, then that is a greater energy expenditure that can be very fatiguing. Clinicians use different design characteristics in foot orthotics to facilitate the windlass mechanism and also to make walking easier and more efficient. In the event the windlass can be established easily when walking or running is not going to need very much and the foot could naturally support its own arch.