Background
A regularly prescribed design variable in foot orthoses (FOs) is the addition of an extrinsic rearfoot post, a feature which can be angled medially or laterally and is intended to control movement of the calcaneus during the stance phase of gait [1]. This study aims to investigate whether introducing incremental changes in this feature will produce a linear trend in the user’s frontal plane biomechanical responses, and whether responses vary between normal and pronated feet.