title: A unified theory for the energy cost of legged locomotion.
abstract: Small animals are remarkably efficient climbers but comparatively poor runners, a well-established phenomenon in locomotor energetics that drives size-related differences in locomotor ecology yet remains poorly understood. Here, I derive the energy cost of legged locomotion from two complementary components of muscle metabolism, Activation-Relaxation and Cross-bridge cycling. A mathematical model incorporating these costs explains observed patterns of locomotor cost both within and between species, across a broad range of animals (insects to ungulates), for a wide range of substrate slopes including level running and vertical climbing. This ARC model unifies work- and force-based models for locomotor cost and integrates whole-organism locomotor cost with cellular muscle physiology, creating a predictive framework for investigating evolutionary and ecological pressures shaping limb design and ranging behaviour.
authors.affiliation: Department of Anthropology, Hunter College, 695 Park Avenue, New York, NY 10065, USA New York Consortium for Evolutionary Primatology, New York, NY, USA herman.pontzer@hunter.cuny.edu.
authors.forename: Herman
authors.identifier: http://orcid.org/0000-0003-2397-6543
authors.initials: H
authors.lastname: Pontzer
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001696:Biomechanical Phenomena; D004734:Energy Metabolism; D007448:Invertebrates / Q000502:physiology*; D008124:Locomotion; D008954:Models, Biological; D014714:Vertebrates / Q000502:physiology*
keywords: biomechanics; energetics; locomotion