by DeeAnn Dougherty
Reprinted with permission from Race Center Northwest, June/July 2002
When you first get up in the morning you notice a terrible pain under your left heel. It hurts when you're standing, walking, and when you get up from sitting. But, most importantly for a runner, it hurts when you run, which is a disappointment because you had recently increased your mileage to train for your first marathon. Your doctor or physical therapist has recommended that you be fitted with foot orthotic devices. Just what is a foot orthotic, anyway?
To clear up a misconception, it is not an arch support. It is a device that fits in the shoe and affects the mechanics of foot and leg function in walking and running. So to understand orthotics, we need to understand normal walking and running gait.
Normal gait involves the motions of pronation and supination. Pronation and supination usually describe a combination of movements in the foot and ankle, but might be easier understood as the loading and unloading that occur at other joints as well. An example is the baseball pitcher winding up (loading) and then throwing the ball (unloading). In gait, the loading (pronation) occurs as the foot hits the ground and rolls inward, taking the rest of the leg with it. This motion is controlled by muscles of the foot, ankle, knee, hip, and pelvis, but most notably by the soleus muscle deep in the calf. Pronation allows for shock absorption and accommodation to the ground surface. Supination is the motion in the opposite direction, where the foot rolls back outward, creating stability in the foot and leg, allowing for a strong unloading as the body is propelled forward. An easy way to see this motion is to stand with equal weight on each foot, and, without moving your feet, twist your trunk to the right. Your left foot is now pronated and your right foot is supinated. Twist to the left and the opposite is true.
Several factors determine the amount and duration of pronation and supination. Some feet are flat, with little arch, and tend to pronate excessively and/or stay pronated too long while the foot is on the ground. Feet with a high arch may allow less pronation, and therefore less shock absorption. The bony alignment of the foot with the leg, or of the rear of the foot with the forefoot, can influence the amount and timing of pronation and supination. Weakness and/or tightness in any of the muscles that control pronation (the soleus, the hip external rotators) or stiffness in the joints of the foot and leg can have an effect as well. Everyone's biomechanics are unique, so it is important to have a full biomechanical examination.
The purpose of the biomechanical exam is to identify not only the location of the pain but also to find the possible causes. It includes a thorough history, evaluation of bony alignment, and an assessment of static and dynamic leg and trunk mobility and strength. Gait is examined with or without a treadmill and video analysis.
Let's return to your left heel pain. You're diagnosed with plantar fasciitis because of tenderness of this fibrous band at its attachment to the heel. The biomechanical exam revealed that you have flat feet, excessive pronation, and tightness in the calf muscles. And your current running shoes do not adequately control the pronation. So there are basically two areas of focus: treat the plantar fasciitis directly, and, more importantly, address the suspected causes, namely the excessive pronation and perhaps a too ambitious increase in mileage. Biomechanical treatment may include stretching the calf muscles (tight calf muscles increase pronation) and changing to a more stable shoe that assists in controlling pronation. Referral to a coach to assist you in developing a training plan could also be helpful. If these measures fail to eliminate the heel pain, then orthotics are the next step.
While studies have proven that orthotic devices effectively prevent injury and assist in recovery, exactly how they work their magic is an ongoing debate in the medical community. The best way to describe what an orthotic does is it brings the ground up to meet the foot, rather than the foot having to go down to meet the ground. A University of Calgary study recently concluded that orthotic devices might work by decreasing the work required of muscles.
Off–the-shelf orthotics are available at many running stores; some of them can even be heated up and molded to your feet. Custom orthotics are made to fit you and only you, and to address your biomechanics. There are as many different ways to make custom orthotics as there are practitioners making them. In some instances, a plaster cast is taken of your foot in order to form a mold. Other methods include heating material and molding it to the foot or using foam to make an impression. The different types of materials used to make orthotics are endless. There's also great debate regarding positioning of the foot at the time of molding, and where and how much correction (posting) to add to the orthotic to assist controlling the foot and leg motion. This is why orthotic prescription is more art than science. You could receive four totally different looking pairs of orthotics from four different practitioners, but all four could achieve the same result.
When you receive your orthotics, you will be instructed in how to break them in, gradually increasing your wearing time and the activities you do in them. You should remove the insole from your running shoe so that your orthotic sits flat in the bottom of the shoe. The final consideration is finding a shoe to work in tandem with your orthotics.
There are basically three kinds of running shoes: motion-control, stability, and cushioned. The motion-control shoe controls excessive pronation. The cushioned shoe absorbs shock for the foot that underpronates. The stability shoe is a combination of the other two; it provides some motion control and some cushioning for the foot that doesn't need a lot of either.
Your practitioner or a running shoe specialty store should be able to guide you towards the right shoe for you and your orthotics. Remember that your orthotics need appropriate shoes, just as a house requires a sturdy foundation. With the right combination, along with sensible training, you should enjoy many years of healthy running.