What is pronation? Do I need stability shoes?

What is pronation? Do I need stability shoes?

Pronation. Supination. What are they and what shoe do I need?

The human body has the ability to move in incredibly intricate patterns. To describe a specific movement activity to someone else can be quite difficult. To simplify things, we describe in terms of motion in 3 planes. This appears much like the X-axis and Y-axis and Z-axis of geometry and trigonometry. So nodding your head yes and no happens in one plane, bringing you ear to your shoulder happens in a second plane and turning your chin over your shoulder happens in a third plane.

So far this sounds straightforward. Most motions that occur during functional activities are combinations of motion in all 3 planes. Pronation describes the combined motions of the foot and ankle joint that occur in all 3 planes. This should happen with every foot step- running or walking. It looks like a flattening of the arch with the leg rotating towards midline, and the shin getting closer to the top of the foot. Basically like you are trying to smoosh the foot into the ground. The body uses this motion to absorb shock and create a flexible dynamic foot. This helps the body adapt to the surface the foot is on. By absorbing shock like a coiled spring, it allows the force of body weight smooshing it in to the ground to be transformed into the spring of the next step.

When the foot first hits the ground, pronation occurs to absorb the load of your body weight and prepares to explode into the next step. As your weight moves forward over the foot, and gets ready for toe-off, the foot transforms into a rigid propulsive lever in order to transmit force efficiently. Similar to a golf club made of rigid steel or carbon fiber, a rigid foot is most effective for transmitting force. Try smacking a golf ball with a club made of light plastic or soft rubber- it's an ineffective means of transmitting force. This transformation of the foot into a more rigid structure is called supination and is the opposite of pronation.

The problems that occur at the foot often lie with a foot that is pronating too late with walking or running, leaving the foot flexible and mobile when it is time to push off. The body is forced into pushing off a flimsy surface, which puts undue stress on the muscles and tendons responsible for slowing the downward force and propelling you forward. The goal of many shoe inserts and stability shoes is to reduce the amount of pronation the foot can go into or reduce the speed of that pronation so the body has time to supinate in time for push off.

Pronation is a passive process that body weight coming into the ground creates. The muscles of the leg—from butt to toes—are charged with controlling this force and exploding into supination and push-off. If that muscular control is not there—weakness, control problems, anatomical variations—pronation or "over-pronation" can become a problem.

As a physical therapist, my task is to examine the client's current movement patterns and correlate those with symptoms. I frequently find that weakness and poor control tend to be at least as common as anatomical problems in causing pain or inefficiency. Another common scenario is the client whose body understands that it cannot adequately control pronation and will keep the body in supination the whole time. This works great for speed and energy transfer, but shock absorption is a big problem for these athletes and they tend to get pain in the joints above the ankle. The athlete who relies on this strategy is the target audience of the "cushion" shoe.

The height of the arch at rest does not determine how well the body can function.

Pronation or tri-plane loading happens above the foot as well. When the arch on inside edge of the foot lowers and the lower leg turns in, it allows the knee to bend and causes the thigh to rotate in. This flexes the hip and causes the thigh to come towards midline and pulls the pelvis forward. This causes flexion, side bending and rotation in the lumbar spine. And then, supination allows this tightly coiled system to explode and forward motion is generated. So it's true: the hip bone is connected to the knee bone and the knee bone is connected to the foot bone. And it's easy to see why knee pain and groin pain and back pain can all come from a timing issue down at the foot.

So what's a runner to do? If you are running pain free and at a pace you are happy with—do nothing. You've entered running bliss. Don't let anyone ruin it. If you want to run faster and especially if you have pain related to your running, you have options. Find someone who can look at your running mechanics, and assess your timing, flexibility, anatomical alignment and strength; and who can make recommendations about shoes and/or inserts that will work with your unique variances.

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