Plantar fasciitis can feel like a living prison, where every step is agony. The pain is typically one of tired, unresponsive and aching feet, often with sensations of intense burning and heat. The feet feel like flat brittle plates; as if you are walking on the bones. Often the shoe size can increase as the feet become more painful.

What is the Anatomy of the Foot?

Working naturally, the toes work like a spread of tentacles across the floor clawing you forward. The toes originate in the mid-foot at the base of the long foot bones, the metatarsals. Behind the toes, the natural arch of the foot is created by a span of tarsal bones slotted around a natural crescent, like the shaped blocks of stone in the arch of a sandstone bridge.

The role of the medial arch is to be springy and dynamic to dissipate the compressive forces bearing down from above. Ideally, it also acts as a 'pincer' to shunt you forward as you walk. The intrinsic muscles of the foot and lower leg work together to pinch the sides of the arch together to provide the propulsion. 

What is the Role of the Plantar Fascia?

The plantar fascia is a pad of gristley tissue we walk on that protects the feet bones from contact with the ground. The planter fascia is some of the densest fibrous tissue in the body. It resembles a thick expanse of calico spanning the underside of the foot from the heel bone to the front of the the metatarsals. The plantar fascia is our foot padding. 

The more we go without shoes and thicker the gristle-pad of the fascia becomes. People who go bare-footed a lot - and indigenous cultures that don't wear shoes at all - have an extremely thick layer of fascia, like the leather sole of the shoe itself. And because their toes are not trapped away in shoes these people are unlikely to suffer plantar fasciitis. 

How the Muscles Work to Help the Plantar Fascia

Even at the best of times, it's a tall order keeping the arches of the feet from flattening under the weight of the body. A secondary role of the plantar fascia is to function like a bowstring under the foot to help keep the arch suspended. Important in this role of keeping the arch high are the muscles of the foot and the lower leg. 

The very important calf and shin muscles also help hold the arch up. They do this by crossing underneath the foot at the peak of the arch like an elastic stirrup that slings the mid-foot high. They do this in combination with a very important 'spring ligament' which you can see in the diagram above. 

Foot and calf muscles pinch the arch up and add spring to the step. This helps greatly with push off during walking. The better they arts the easier the walking. The ballet dancer Nijiinsky was famous for having a very high leap, made possible by a powerfully strong bowstring action of his underfoot. 

What Causes the Pain of Plantar Fasciitis?

When the foot arch drops for any reason the plantar fascia is chronically stretched. The most usual cause for the arch dropping is subclinical lower back dysfunction, where there is a subtle interference with the nerve supply getting through to the muscles of the lower leg. This developing problem may be associated with back pain, which will need its own treatment.

But there also may be no back pain at all. In these instances, plantar fasciitis can come on after a period of forced inactivity where all the leg muscles get weaker, or after a weight gain where the arches are unable to hold up bodyweight. 

Exercises for Plantar Fasciitis Also Involve Strengthening the Arch of the Foot