Consistent inconsistencies in braking: a spatial analysis

Abstract

The dynamic system that is the bipedal body in motion is of interest to engineers, clinicians and biological anthropologists alike. Spatial statistics is more familiar to public health researchers as a way of analysing disease clustering and spread; nonetheless, this is a practical approach to the two-dimensional topography of the foot. We quantified the clustering of the centre of pressure (CoP) on the foot for peak braking and propulsive vertical ground reaction forces (GRFs) over multiple, contiguous steps to assess the consistency of the location of peak forces on the foot during walking. The vertical GRFs of 11 participants were collected continuously via a wireless insole system (MoticonReGo AG) across various experimental conditions. We hypothesized that CoPs would cluster in the hindfoot for braking and forefoot for propulsion, and that braking would demonstrate more consistent clustering than propulsion. Contrary to our hypotheses, we found that CoPs during braking are inconsistent in their location, and CoPs during propulsion are more consistent and clustered across all participants and all trials. These results add to our understanding of the applied forces on the foot so that we can better predict fatigue failures and better understand the mechanisms that shaped the modern bipedal form.

Introduction to the theme issue ‘Biological anthroengineering’

“…Introduction to the theme issue 'Biological anthroengineering' Patricia Ann Kramer 1,2 and Michael A. Berthaume 3 1 Department of Anthropology, and 2 Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195-3100, USA 3 Division of Mechanical Engineering and Design, London South Bank University, London, UK PAK, 0000-0002-6435-9130; MAB, 0000-0003-1298-242X While using the theoretical foundation and methodological techniques of mechanical engineering to understand living creatures is not unique to biological anthropologists, in 2016, the authors began discussing an integration of anthropology and engineering that is more than simply a borrowing of ideas of one discipline from another. We imagined-and continue to develop-this vision of anthroengineering [1].…”

“…The first four studies focus on different aspects of locomotor biomechanics in humans. Hammerberg & Kramer [2] analysed centre of pressure (CoP) in the foot during the braking and propulsive phases of walking. Applying cluster analyses from spatial statistics, they assessed the consistency of the location of the CoP across contiguous steps during human walking trials.…”