Plantar fasciitis is a condition affecting the plantar fascia: a thick band of connective tissue that runs along the sole of the foot, connecting the heel bone (calcaneus) to the base of the toes. The plantar fascia helps support the arch of the foot and absorbs forces during walking, running, and standing.
Repeated loading or excessive strain can cause microscopic damage where the plantar fascia attaches to the heel bone. In the early stages, inflammation may contribute to symptoms. Over time, however, the tissue may undergo degenerative changes (sometimes referred to as plantar fasciosis), which can make recovery more prolonged.
The Windlass Mechanism
Understanding the windlass mechanism helps explain why plantar fasciitis can be persistent. During walking, as the toes bend upward (dorsiflex) before push-off, the plantar fascia tightens around the metatarsal heads like a cable on a windlass. This raises and stiffens the arch, allowing the foot to function as an efficient lever during propulsion.
Repeated loading of this mechanism, particularly in people with tight calf muscles (gastrocnemius and soleus) or limited ankle flexibility, increases stress where the plantar fascia attaches to the heel bone. This is one reason why calf and Achilles tendon stretching is commonly recommended as part of plantar fasciitis management.