Shoe Glossary: Shank

All about shoe shanks

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A shank is a supportive structure that sits between the shoe's insole and outsole, and runs underneath the arch of the foot. The shank supports the foot and is what gives a shoe structure.

Shanks can be made from a variety of materials, including steel, plastic, fiberglass and Kevlar. They're mostly found in work boots. They are what gives the boots their shape, and they stiffen the outsoles for a more stable fit.

If you've ever tried on a pair of sturdy work boots, they probably felt stiff and uncomfortable, but that rigidity actually contours your feet and provides and more comfortable fit.

Shanks in Orthotic Footwear:

Pronation is what allows us to transfer weight from our heels to the balls of our feet while walking. In normal pronation the outside part of the heel makes contact with the ground and then the foot rolls inward by about 15 percent. The feet support the body without a problem, but most people don't have the perfect feet or gait.

If you have flat feet, you probably overpronate, meaning the outside of your heel makes contact with the ground first and then the foot rolls inward by more than 15 percent. If you have high arches, you probably underpronate, meaning the outside of the heel hits the ground, but the foot doesn't roll inward as much as it should. In each of these cases body weight is not evenly distributed.

Pronation could be to blame if you experience arch pain, knee pain, plantar fasciitis or any other discomfort. The easiest thing you can do to alleviate the pain is by making sure you have proper footwear. Your shoes should have a firm heel with a sturdy shank or midsole to effectively support and stabilize the foot.

There are many manufacturers that make comfortable and stylish orthotic shoes that will improve your pronation. You could also purchase orthotic inserts to put into shoes you already own that aren't as supportive as they should be.

Shanks in Sneakers:

Running and training shoes don't have shanks like those in heavy work boots. Fitness activities require the foot to flex, and shanks prevent that natural flexion.

Shanks are like splints. While they're good in sturdy work boots and orthotic shoes, they isolate the foot from movement. Healthy feet need to flex to some degree, especially during fitness activities.

Still, most running shoes, except the most lightweight and flexible ones, are reinforced with shanks. In some sneakers the shank is incorporated into the arch of the shoe so it supports and stabilizes the foot. When the heel lifts, the arch bends as weight is transferred to the ball of the foot, but with the shank under the arch, the shoe bends at the toes. The shank does add weight, but it's a very minimal amount.