title: Gait as solution, but what is the problem? Exploring cost, economy and compromise in locomotion.
abstract: Many studies have examined how legged mammals move, defining 'what' happens in locomotion. However, few ask 'why' those motions occur as they do. The energetic and functional constraints acting on an animal require that locomotion should be metabolically 'cost effective' and this in large part determines the strategies available to accomplish the task. Understanding the gaits utilised, within the spectrum of gaits possible, and determination of the value of specific relationships among speed, stride length, stride frequency and morphology, depends on identifying the fundamental costs involved and the effects of different movement strategies on those costs. It is argued here that a fundamental loss associated with moving on limbs (centre of mass momentum and energy loss) and two costs involved with controlling and replacing that loss (muscular work of the supporting limb during stance and muscular work of repositioning the limbs during swing) interact to determine the cost trade-offs involved and the optimisation strategies available for each species and speed. These optimisation strategies are what has been observed and characterised as gait.
authors.affiliation: Faculty of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 1N4, Canada. Electronic address: jbertram@ucalgary.ca.
authors.forename: John E A
authors.initials: JE
authors.lastname: Bertram
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D005684:Gait / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*
keywords: Gait; Locomotion