An overpronator does not absorb shock efficiently. Imagine someone jumping onto a diving board, but the board is so flimsy that when it is struck, it bends and allows the person to plunge straight down into the water instead of back into the air. Similarly, an overpronator's arches will collapse, or the ankles will roll inwards (or a combination of the two) as they cycle through the gait. An individual whose bone structure involves external rotation at the hip, knee, or ankle will be more likely to overpronate than one whose bone structure has internal rotation or central alignment. An individual who overpronates tends to wear down their running shoes on the medial (inside) side of the shoe towards the toe area.