A Windlass is the tightening of a rope or cable around a pivot point. The plantar fascia acts like a cable between the calcaneus and its distal insertion into the proximal phalanyx at the metatarsal phalangeal joints. When the toes are dorsiflexed (as in forefoot rocker), the heel and toes SHOULD become approximated, as the plantar fascia shortens from its winding around the metatarsal head, contributing to supination of the foot.
Plantar Faciitis is an inflammation and/or injury to the plantar fascia, which is similar to a tight cable or wire attached to the calcaneus and the metatarsophalageal joint.
The windlass mechanism describes the manner by which the plantar fascia supports the foot during weight- bearing activities and provides information regarding the biomechanical stresses placed on the plantar fascia.
Dorsiflexion during propulsive phase of gait winds plantar fascia around head of metatarsal. This winding to plantar fascia to metatarsals shortens the distance between the calcaneus and metatarsals to elevate medial longitudinal arch. This shortening of plantar fascia during dorsiflexion is the essence of windlass mechanism principle. Irregularity in this bio mechanics results in plantar fasciitis
This windlass mechanism is somewhat more complex. According to a study of Boysen-Moller, some decades ago, there is a disctinct difference between the big toe and the other toes. Because of the two sesame bones under the big toe the radius of the windlass is much bigger here. The consequence is that dorsiflexion of the big toe induces much more increase in tension on the plantar aponeurosis than the smaller toes. According to Boysen-Moller this has to do with the walking pattern: In normal 'slow' gate the unwinding of the foot takes place over the smaller toes, increasing the tension of the plantar aponeurosis just a bit at push off of the foot. When running the emphasis of unwinding of the foot takes place over the big toe, increasing the tension of the plantar aponeurisis much more (because of the bigger windlass radius.
You might say we have a shifting gear in our foot to balance the load on the arch of the foot under different loading circumstances.
Now ho may this lead to plantar fascitis? This might be one possibility: If the arch of our foot flattens or when our leg is more exorotated (becaause of knee or hip or loewe back problems) the emphasis of unwinding of the foot takes place over the big toe, even though we are not running.. Consequently, with every step the tension on the aponeurosis is that of 'running' level. This too high tension, over a longer period of time, may induce irritation and inflammation.
Heel spur could be caused by the same mechanism. Tension induced by the big toe is located more medially on the aponeurosis and so on the medial side of the calcaneus (origo aponeurosis). Prolongued tension may lead to calcification of this insertionpoint.
If desired I can try to provide the article referenced.
Dear Jan-Paul Wingerden. Thanks for your valuable information. Kindly provide the article so that I can quote it in my research work.
Dear arun,
Article is in my paper collection. Will make a pdf and provide it januari 6! (sorry for the delay (holidays)).
Dear Jan Paul Wingerden. Thank you for sharing the articles and i will go through it .
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