Models of Energetically Optimal Locomotion in Cursorial Mammals

Polet, Delyle Thomas

Models of Energetically Optimal Locomotion in Cursorial Mammals

dc.contributor.advisor	Theodor, Jessica M.
dc.contributor.advisor	Bertram, John Edward Arthur
dc.contributor.author	Polet, Delyle Thomas
dc.contributor.committeemember	Pieper, Jeffery Kurt
dc.contributor.committeemember	Syme, Douglas A.
dc.contributor.committeemember	Kuo, Arthur D.
dc.contributor.committeemember	Carrier, David R.
dc.date	2020-06
dc.date.accessioned	2020-02-20T15:24:19Z
dc.date.available	2020-02-20T15:24:19Z
dc.date.issued	2020-02-14
dc.description.abstract	It is widely held that cursorial mammals use gaits that minimize the energetic cost of locomotion, but it is hard to compare alternative strategies in real organisms. In this thesis, I show how simple models can inform and predict the gaits used by cursorial mammals from an energetics perspective. A simple work optimization model predicts how human subjects reduce their takeoff velocity and "bounciness" while running in reduced gravity. This work-based perspective is extended to quadrupeds using trajectory optimization, where it is shown that an additional term– the so-called force-rate penalty– is necessary to explain some features of canid locomotion. The shape of ground reaction forces, leg sequence at slow to moderate speeds, changes in duty factor at moderate to fast speeds, and the walk-trot transition are all predicted by this planar model. Next I use this model to show how changing pitch moment of inertia affects energy-optimal gait choice, matching gait preferences between dogs, horses, giraffes and elephants. Finally, I compare various modelling approaches used for four-legged mammals, and show how center-of-mass considerations alone do not explain the typical, four-beat walking gait used by most cursorial quadrupeds– despite the success of the center-of-mass approach in humans, as demonstrated in this very thesis. These results show that energetic optimization can be remarkably predictive of gait choice in mammalian cursors, even with a small number of modelling components. Where the predictions are deficient, they point to missing levels of complexity that could be added in future models.	en_US
dc.identifier.citation	Polet, D. T. (2020). Models of Energetically Optimal Locomotion in Cursorial Mammals (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.	en_US
dc.identifier.doi	http://dx.doi.org/10.11575/PRISM/37581
dc.identifier.uri	http://hdl.handle.net/1880/111658
dc.language.iso	eng	en_US
dc.publisher.faculty	Science	en_US
dc.publisher.institution	University of Calgary	en
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.	en_US
dc.subject	optimization, comparative biomechanics, locomotion, models, energetics	en_US
dc.subject.classification	Literature--Comparative	en_US
dc.subject.classification	Animal Physiology	en_US
dc.subject.classification	Zoology	en_US
dc.subject.classification	Applied Mechanics	en_US
dc.title	Models of Energetically Optimal Locomotion in Cursorial Mammals	en_US
dc.type	doctoral thesis	en_US
thesis.degree.discipline	Biological Sciences	en_US
thesis.degree.grantor	University of Calgary	en_US
thesis.degree.name	Doctor of Philosophy (PhD)	en_US
ucalgary.item.requestcopy	true	en_US