The windlass is that equipment that are used by the sailors on yachts to wind the rope about to help to make it easier to maneuver the boom. Within the foot there exists a mechanism that is referred to as the windlass mechanism that gets its name from this equipment used on yachts. There is a ligament like structure beneath the foot called the plantar fascia which is at one end connected to the bottom of the heel and at the other end to the great toe. When we're walking and the heel comes off the floor, the foot rotates around the big toe or hallux where this ligament is attached, tightening the plantar fascia as it winds around the windlass of the first metatarsal head. This is the windlass mechanism of the foot. This is a essential function as that ligament is what supports the arch of the foot, therefore it is required to function correctly and quickly for normal foot biomechanics. It is the foots own natural arch support mechanism.
There are a number of conditions related to the windlass mechanism not functioning effectively. Should the windlass mechanism doesn't work, then the arch of the foot will collapse from the lack of support and a range of disorders may develop because of that for example hallux valgus and plantar fasciitis. The reason for the windlass not working correctly can be multiple like the force necessary to establish it simply being too high, so the body needs to work harder to make the windlass function. If that hard work can make it work, then that is a greater energy expenditure that could be very fatiguing. Podiatrists use different design characteristics in foot supports to enhance the windlass mechanism and also to make walking less difficult and more effective. In the event the windlass can be established easily during walking or running is not going to require so much energy and the foot will naturally support its own arch.