Pronation is essential to our normal gait, but for some runners, uncontrolled overpronation may lead to problems. For decades, lab studies have noted a correlation between overpronation – especially excessive foot eversion – and lower limb complaints. Historically this insight led many brands down the route of heavy motion control shoes. These shoes incorporate a rigid support structure within the medial side of the rearfoot and under the arch to control heel eversion and increase rearfoot stability.