Ontogenetic changes in foot strike pattern and calcaneal loading during walking in young children

Abstract

A B S T R A C TThe 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.

Baby steps towards linking calcaneal trabecular bone ontogeny and the development of bipedal human gait

“…Finally, we refer to all non‐adult individuals as ‘juveniles’. The gait of juveniles differs substantially from that of adults (Levine et al ; Zeininger et al ). Juveniles have a wider walking base, smaller stride lengths, and lower walking speeds.…”

“…Independent walking starts roughly between 10 and 17 months, and at this point a child is able to move forward unassisted (Zeininger et al ), although with a gait that differs from that which develops through childhood. At 1 year of age the tibialis anterior is too weak to dorsiflex the foot during swing, resulting in a plantigrade foot at touchdown (Rose & Gamble, ; Zeininger et al ). One‐year‐olds are also unable to create enough torque at the ankle to propel themselves forward into swing (Hallemans et al , ).…”

“…Children start to walk between 10 and 16 months of age (Zeininger et al ). This new mechanical stimulation combined with increases in body size is predicted to initiate reorganization of the trabecular architecture throughout the calcaneus.…”

“…We therefore predict that bone volume fraction will diverge from the rest of the calcaneus by increasing at a greater rate and to a higher value after walking commences. Heel strike develops at roughly 18–24 months of age (Zeininger, ) but is expected to be difficult to detect in trabecular structure because the part of the heel that strikes the ground is made of cartilage at the point the heel strike phase of gait develops. The transient force produced by heel strike may increase bone volume fraction in the posterior compressive band of trabeculae (Fig.…”

Big issues for small feet: developmental, biomechanical and clinical narratives on children's footwear

“…The longer-term effects of habitual (barefoot running and) walking on biomechanical, health and motor performance outcomes remain to be determined [ 25 ]. Looking beyond morphology and anthropometric parameters is an essential shift in this area and recent work looking at the ontogenetic changes in foot strike patterns in early walking [ 26 ] highlighted the importance of understanding the structure-function relationships of the developing foot, as well as the impact of the foot-shoe interaction. Understanding how footwear and their materials (e.g.…”