Form and Function in the Typically Developing Infant

Abstract

This thesis presents the form and function in the lower limb of typically developing infants during the first year of autonomous walking. Lower limb motion analysis and 3D ultrasound of the gastrocnemius is captured at 3 time points from 12 to 24 months of age. Additionally, an infant finite element foot model was developed to explore bone adaptation in the calcaneus across the first year of walking. In general, it was observed that infant kinematics and kinetics converges towards adult like characteristics by 24 months of age. Infant gastrocnemius development can be in part explained by the changing ankle joint torques. Moreover, the increase in calcaneus cortical bone density and bone fibre directions is driven by the changing foot centre of pressure and muscle and ligament forces. These findings fill a gap in knowledge that is missing in infant biomechanics in the literature and anatomy texts.