The ankle-foot rollover shapes used by nondisabled
ambulators wearing shoes of different heel heights were
measured and characterized in this study. Ankle-foot rollover
shapes are the effective rocker (cam) shapes that the
foot/ankle complex conforms to during the period between
heel contact and opposite heel contact of walking. During
this period of gait, the body rotates over, or rolls over, the
stance leg (where “leg” refers to the entire lower limb and
foot). When shoes are worn, their effects are also included
in the ankle-foot rollover shapes [11,12].
The hypothesis of the study, based on results of preliminary
experiments [11,12] was that the nondisabled
human adapts (primarily at the ankle) to maintain a similar
rollover shape for a wide range of heel heights. This
similar shape would allow the head, arms, and trunk
(HAT) unit [13] to roll over the leg in a similar manner
with shoes of different heel heights, leading to similar
movements of the body’s center of mass. A change was
expected in the vertical positioning of the rollover
shapes—and hence in the effective length of the leg—
because the taller shoes would position the ankle higher
above the ground than the lower-heel shoes.
A