While running seems like a simple activity, it is actually a complicated movement that puts a lot of stress on the joints, bones and ligaments of the body. Consequently, choosing the right shoe is an important step in increasing performance and decreasing injury risk. You should select running shoes based on your foot type. While other considerations are important, such as trail versus road shoes, your foot type dictates the amount of cushioning, stability and motion control you need. The best way to determine your foot type is to visit a local specialty running shop. Professionals there can measure your arch type, stride and gait and summarize your shoe needs for future reference.
Running shoe design is based on the idea of pronation. Pronation is the natural rolling of your ankle from outside to inside during foot strike. In other words, proper running mechanics involve striking the ground on the outside of your heel and rolling toward your big toe before pushing off again. Pronation is a good thing: it helps your lower extremities absorb shock and store energy. Neutral runners who pronate correctly do not depend on their shoes to correct their form. Neutral runners can select from a large variety of shoes, even minimal or barefoot models. However, runners with problematic foot arches or incorrect form may pronate too much or too little and require specific qualities from their running shoes.
Overpronators run with excessive ankle rolling. Even when standing, severe overpronators exhibit ankles that angle inward. They also tend to have flat feet or bowed legs. Overpronation can cause a plethora of injuries, especially in the knees, ankles and Achilles tendons. If you overpronate, you should select a shoe with extra stability and motion-control. Motion-control shoes are firm and straight; they do not curve at the tip. The lack of flexibility along the midsole prevents the foot from rolling too far inward during your foot strike.
Underpronation, also called supination, is less common than overpronation. Unlike overpronators, underpronators have inflexible feet and high arches. When they land, their feet are unable to roll inward. While this places less rotational stress on the ankles and knees, it prevents any kind of shock absorptions. This additional force can result in fractures, ligament tears and muscle strains as the legs compensate for the impact. Underpronators require shoes with increased cushioning and flexibility. If you underpronate, stability or motion-control shoes may compound the problem by further preventing pronation.