Conway McLean, DPM, Journal columnist

People like to pigeonhole, it’s something we humans have a tendency to. Are you a Republican or a Democrat? Are you a vegetarian or a carnivore? Some categorization is purely biologic: do you have type A blood or B negative? The same could be said for one’s foot type. Do you have a high or low arched foot?

Technically, this is asking if you are a pronator or a supinator: does your arch lower more or is it raised? These terms refer to some important characteristics of the human foot that have a tremendous effect on our musculoskeletal system, even our lives and livelihoods, our health and well-being. This may sound a bit dramatic but it’s really quite accurate.

There is a certain percentage of individuals who have a perfectly normal foot type with the proper alignment of joints, the correct tension on the multiple tendons and muscles. There are people with a perfect arch. But this is not the norm since most of us tend towards one side or the other of this equation, an arch that is too high or one too low. Or, quite distinct, one can have an arch which lowers too much at a certain point in the gait cycle (i.e. when walking) but otherwise is normal. Some pronation, basically lowering of the arch, is normal, proper, and healthy, but those with excessive amounts (referred to as pronation syndrome), tend to have problems associated with their abnormal function and poor biomechanics.

The joint below the ankle, the subtalar joint, is a critical player in this discussion. This is the articulation that allows the foot to move side to side, unlike the ankle joint which is a simple hinge type mechanism. Motion of the STJ (sub-talar joint) enables the foot to adapt to different surfaces. A specific motion of this joint allows the foot to assume a more stable position for pushing off, vital to propelling the body forward at the beginning of each step. Another vital function of this joint is the absorption of shock, necessary with each step. (Don’t discount the cumulative effects of this subtle but extremely recurrent impact.)

It may be understandable how too much pronation could cause problems to the foot. Like planter fasciitis, whereby the ligament supporting the arch is getting stretched from excess pronation when the arch collapses. But consequential is the effects to the ankle, leg, hips, and back. This is a result of anatomy: the talus bone, which is the bottom component of the ankle joint, turns inward when the arch lowers. Because the talus is locked in between the ankle bones, the lower leg has to turn when this bone turns, as with excess pronation. And this changes things right up the kinetic chain of body mechanics.

Again, pronation is a normal motion and occurs with each and every step. But in nature, as in most everything, too much of anything is a bad thing. Excessive pronation is responsible for a multitude of pathologies, from knee pain and degeneration to chronic back pain. A plethora of foot problems are correlated with the abnormal motion associated with pronation syndrome. But it’s essential to understand some pronation is required for normal and healthy gait.

The extra motion of too much pronation, like a tiny sprain, but one occurring with each step, ten thousand a day, three hundred and sixty days, will take its toll somewhere. The repetitive nature of this pathology is what leads to symptoms for most. Walking for one day with too much pronation won’t strain anything, none of the multitude of tendons, ligaments, and structures involved. But do that a hundred million times (roughly the number of steps an active individual might take over their adulthood) and the development of some related problem becomes understandable.

One consequence of pronation syndrome is reduced tension on the Achilles tendon, allowing it to shorten over the years. This change results in an alteration of gait and abnormal stress to a variety of structures. If you pronate excessively, you probably have a tightened Achilles tendon-muscle complex. Want to help your biomechanical functioning and musculoskeletal system? Stretch out your Achilles tendon (a task requiring an inordinate amount of time to achieve).

Probably the most effective deterrent to excessive pronation would be some type of arch support. As regular readers likely know, this is a touchy subject. Just to be clear, an orthotic is a device that is custom-made. This means the foot, knee, elbow, or whatever structures is being fitted, must be scanned, imaged, casted, etc., in some way to be called an orthotic. Anything that is prefabricated, i.e. taken off a shelf, is not an orthotic.

Experts claim a majority of knee replacements could be prevented if the suffering individuals had worn properly prescribed foot orthotics years prior. Obviously, this is impossible to prove but the message is relevant. The feet are the foundation for the body, as the cliché so accurately proposes.

The time and expertise to properly prescribe and effectively fit a foot orthotic is significant, but the benefits to the musculoskeletal system, upon which we literally depend, are many. They can relieve pain, improve quality of life, enhance cardiovascular health, and more, all by reducing the deleterious consequences of too much pronation.

Of this fact, many Americans are thankful, standing and walking, going about their day. They are ‘hyper-pronators’ who are on their feet, with their excess pronation controlled by their prescription arch supports. But a more appropriate term might be their “body supports.” After all, these specialized braces, hidden away inside your shoe, are supporting everything, from the top of your head to the tip of your big toe.

EDITORS NOTE: Dr. Conway McLean is a podiatric physician now practicing foot and ankle medicine in the Upper Peninsula, having assumed the practice of Dr. Ken Tabor. McLean has lectured internationally on surgery and wound care, and is board certified in both, with a sub-specialty in foot orthotic therapy. Dr. McLean welcomes questions, comments and suggestions at drcmclean@penmed.com.