A variety of plantar pressure and force measures were explored in 22 healthy individuals with excessive pronation. The measures were obtained while the subjects wore a thin-soled athletic shoe alone, a modified Root foot orthosis made from a neutral cast, and a flat noncast insole with a 6 degrees varus rearfoot post. The data obtained from subjects wearing the noncast insole differed only minimally from those obtained while they were wearing the shoe only. In contrast, the modified Root orthosis had a profound effect on foot function. Heel forces and pressures were reduced, and the rearfoot contact area was increased. Measures of force in the midfoot demonstrated substantial increases in load in this region, but the increase in area associated with the contoured device resulted in no increase in midfoot pressure measurements. Forefoot pressures were reduced both medially and laterally with the cast device in place.