title: Partitioning the energetics of walking and running: swinging the limbs is expensive.
abstract: Explaining the energetics of walking and running has been difficult because the distribution of energy use among individual muscles has not been known. We estimated energy use by measuring blood flow to the hindlimb muscles in guinea fowl. Blood flow to skeletal muscles is controlled locally and varies directly with metabolic rate. We estimate that the swing-phase muscles consume 26% of the energy used by the limbs and the stance-phase muscles consume the remaining 74%, independent of speed. Thus, contrary to some previous suggestions, swinging the limbs requires an appreciable fraction of the energy used during terrestrial legged locomotion. Models integrating the energetics and mechanics of running will benefit from more detailed information on the distribution of energy use by the muscles.
authors.affiliation: Department of Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA. r.marsh@neu.edu
authors.forename: Richard L
authors.initials: RL
authors.lastname: Marsh
authors.forename: David J
authors.initials: DJ
authors.lastname: Ellerby
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Carr
authors.forename: Havalee T
authors.initials: HT
authors.lastname: Henry
authors.forename: Cindy I
authors.initials: CI
authors.lastname: Buchanan
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001717:Birds / Q000378:metabolism / Q000502:physiology*; D004576:Electromyography; D004734:Energy Metabolism; D005260:Female; D006614:Hindlimb / Q000098:blood supply / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D008297:Male; D008863:Microspheres; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism / Q000502:physiology*; D010101:Oxygen Consumption; D005082:Physical Exertion; D012039:Regional Blood Flow; D012420:Running / Q000502:physiology*; D013848:Thigh; D016138:Walking / Q000502:physiology*