Navicular drop is a measurement of the foot that measures how much the navicular bone drops from the rearfoot neutral position to a relaxed position. It is a measure of the arch collapse that can be used in the biomechanical assessment of people. The assumption is that the greater the navicular drop, the greater amount of foot pronation, and the greater risk for overuse injury and other problems. While navicular drop is a valid measure of the dynamic arch height, its link to injury rick is not as clear. A related measurement is that of navicular drift which is a measure of how much the navicular drifts in the transverse plane.