Excessive inward roll of the foot after landing, such that the foot continues to roll when it should be pushing off. This twists the foot, shin and knee and can cause pain in all those areas. If you are an overpronator, you'll find excessive wear on the inner side of your running shoes, and they'll tilt inward if you place them on a flat surface. Knock knees or flat feet contribute to overpronation.
Wear shoes with straight or semicurved lasts. Motion-control or stability shoes with firm, multidensity midsoles and external control features that limit pronation are best. Over-the-counter orthotics or arch supports can help, too. You know you are making improvements when the wear pattern on your shoes becomes more normal. Overpronation causes extra stress and tightness to the muscles, so do a little extra stretching.
