Article

The assumption that the morphology of the human calcaneus reflects high and
cyclical impact forces at heel strike during adult human walking has never been
experimentally tested. Since a walking step with a heel strike is an emergent
behavior in children, an ontogenetic study provides a natural experiment to begin
testing the relationship between the mechanics of heel strike and calcaneal
anatomy. This study examined the ground reaction forces (GRFs) of stepping in
children to determine the location of the center of pressure (COP) relative to
the calcaneus and the orientation and magnitude of ground reaction forces during
foot contact. Three-dimensional kinematic and kinetic data were analyzed for 18
children ranging in age from 11.5 to 43.1 months. Early steppers used a flat foot
contact (FFC) and experienced relatively high vertical and resultant GRFs with
COP often anterior to the calcaneus. More experienced walkers used an initial
heel contact (IHC) in which GRFs were significantly lower but the center of
pressure remained under the heel a greater proportion of time. Thus, during FFC
the foot experienced higher loading, but the heel itself was relatively wider and
the load was distributed more evenly. In IHC walkers load was concentrated on the
anterior calcaneus and a narrower heel, suggesting a need for increased calcaneal
robusticity during development to mitigate injury. These results provide new
insight into foot loading outside of typical mature contact patterns, inform
structure-function relationships during development, and illuminate potential
causes of heel injury in young walkers.
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Langue : ANGLAIS