Waddling and toddling: The biomechanical effects of an immature gait

Abstract

Femoral shape changes during the course of human growth, transitioning from a subcircular tube to a teardrop-shaped diaphysis with a posterior pilaster. Differences between immature and mature bipedalism and body shape may generate different loads, which, in turn, may influence femoral modeling and remodeling during the course of the human lifespan. This study uses two different approaches to evaluate the hypotheses that differences in gait between young and mature walkers result in differences in ground reaction forces (GRFs) and that the differences in loading regimes between young children and adults will be reflected in the geometric structure of the midshaft femur. The results of this analysis indicate that GRFs differ between young walkers and adults in that normalized mediolateral (ML) forces are significantly higher in younger age groups. In addition, these differences between children and adults in the relative level of ML bending force are reflected in changes in femoral geometry during growth. During the earlier stages of human development, immature femoral diaphyses are heavily reinforced in approximately ML plane. The differences in gait between mature and immature walkers, and hence the differences in femoral shape, are likely partially a product of a minimal bicondylar angle and relatively broad body in young children.

Insights on the paleoepidemiology of ancient tuberculosis from the structural analysis of postcranial remains from the Ligurian Neolithic (northwestern Italy)

“…During ontogeny, the orientation of femoral maximum bending rigidity shifts from medio-lateral (ML) to antero-posterior (AP) around 8-10 years of age, due to changes in body proportions and gait patterns (Cowgill, 2008;Cowgill et al, 2010;Gosman et al, 2013), and the femur acquires the adult pattern of anterolateral-posteromedial orientation in late adolescence (Goldman et al, 2009). Tibial shape at mid-shaft, which is roughly triangular in adulthood, progressively develops from a rounder cross section during growth due to an increase in diaphyseal rigidity on the AP plane (Gosman et al, 2013).…”

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

“…Further, as the sagittal orientation of the GRFr (GRFr angle) is a function of the magnitude of the Fy and Fz, we predicted that the GRFr would project only slightly posterior in FFC steps. Early walkers (with less than 6 months walking experience) might also be expected to have relatively higher mediolateral (Fx) GRFs because of wide steps [22] and abducted hips [23]. Therefore, we calculated Fx forces, but Fy and Fz forces were the focus of our study, as they are most relevant to distinguishing between FFC and IHC foot strike patterns.…”

“…In contrast, to achieve initial heel contact (IHC), we hypothesized that a long stride allows the leg to swing through a large arc and, coupled with an adducted hip [23] and a dorsiflexed ankle, positions the heel as the point of contact at touchdown. In this model, the heel contacts the ground relatively far in front of the whole body center of mass, compared to FFC steps, and the COP is under the heel at touchdown (Fig.…”

Long bone cross‐sectional properties reflect changes in locomotor behavior in developing chimpanzees

“…V C 2016 Loading behavior correlates with cortical bone crosssectional geometry in human and nonhuman primates (e.g. Schaffler et al, 1985;Demes et al, 1991;Ruff and Runestad, 1992;Ruff, 2002;Carlson, 2005;Shaw and Stock, 2009;Cowgill et al, 2010). Using this relationship, the locomotor behavior of primates has been inferred from the strength and shape of the midshaft of long bones (Ruff et al…”