William I. Sellers

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Maximum running speed is an important locomotor parameter for many animals-predators as well as prey-and is thus of interest to palaeobiologists wishing to reconstruct the behavioural ecology of extinct species. A variety of approaches have been tried in the past including anatomical comparisons, bone scaling and strength, safety factors and ground reaction(More)
We tend to assume that natural selection will bring about 'optimal' configurations in morphology and behaviour. Jumping locomotion involves large forces and energy costs which, in this non-cyclic activity, are generated anew with each jump. Jumping appears to be, therefore, a major target for optimization. It has been a standard assumption that jumpers will(More)
Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted(More)
It is commonly held that the major functional features of the human foot (e.g. a functional longitudinal medial arch, lateral to medial force transfer and hallucal (big-toe) push-off) appear only in the last 2 Myr, but functional interpretations of footbones and footprints of early human ancestors (hominins) prior to 2 million years ago (Mya) remain(More)
Obtaining quantitative data describing the movements of animals is an essential step in understanding their locomotor biology. Outside the laboratory, measuring animal locomotion often relies on video-based approaches and analysis is hampered because of difficulties in calibration and often the limited availability of possible camera positions. It is also(More)
Unlike all other primates, members of the subfamily Lorisinae are never seen to leap. To investigate the anatomical specializations that are behind the absence of leaping in their locomotor repertoire, a predictive mechanical model of leaping was developed using the lesser bushbaby, Galago moholi, as a size-matched leaping prosimian comparison. This enabled(More)
This study investigates the relation between walking speed and the distribution of peak plantar pressure and compares a traditional ten-region subsampling (10RS) technique with a new technique: pedobarographic statistical parametric mapping (pSPM). Adapted from cerebral fMRI methodology, pSPM is a digital image processing technique that registers foot(More)
This paper uses techniques from evolutionary robotics to predict the most energy-efficient upright walking gait for the early human relative Australopithecus afarensis, based on the proportions of the 3.2 million year old AL 288-1 'Lucy' skeleton, and matches predictions against the nearly contemporaneous (3.5-3.6 million year old) Laetoli fossil footprint(More)