Document Detail


Blood flow in guinea fowl Numida meleagris as an indicator of energy expenditure by individual muscles during walking and running.
MedLine Citation:
PMID:  15731191     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Running and walking are mechanically complex activities. Leg muscles must exert forces to support weight and provide stability, do work to accelerate the limbs and body centre of mass, and absorb work to act as brakes. Current understanding of energy use during legged locomotion has been limited by the lack of measurements of energy use by individual muscles. Our study is based on the correlation between blood flow and aerobic energy expenditure in active skeletal muscle during locomotion. This correlation is strongly supported by the available evidence concerning control of blood flow to active muscle, and the relationship between blood flow and the rate of muscle oxygen consumption. We used injectable microspheres to measure the blood flow to the hind-limb muscles, and other body tissues, in guinea fowl (Numida meleagris) at rest, and across a range of walking and running speeds. Combined with data concerning the various mechanical functions of the leg muscles, this approach has enabled the first direct estimates of the energetic costs of some of these functions. Cardiac output increased from 350 ml min(-1) at rest, to 1700 ml min(-1) at a running speed ( approximately 2.6 m s(-1)) eliciting a of 90% of . The increase in cardiac output was achieved via approximately equal factorial increases in heart rate and stroke volume. Approximately 90% of the increased cardiac output was directed to the active muscles of the hind limbs, without redistribution of blood flow from the viscera. Values of mass-specific blood flow to the ventricles, approximately 15 ml min(-1) g(-1), and one of the hind-limb muscles, approximately 9 ml min(-1) g(-1), were the highest yet recorded for blood flow to active muscle. The patterns of increasing blood flow with increasing speed varied greatly among different muscles. The increases in flow correlated with the likely fibre type distribution of the muscles. Muscles expected to have many high-oxidative fibres preferentially increased flow at low exercise intensities. We estimated substantial energetic costs associated with swinging the limbs, co-contraction to stabilize the knee and work production by the hind-limb muscles. Our data provide a basis for evaluating hypotheses relating the mechanics and energetics of legged locomotion.
Authors:
David J Ellerby; Havalee T Henry; Jennifer A Carr; Cindy I Buchanan; Richard L Marsh
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, P.H.S.     Date:  2005-02-24
Journal Detail:
Title:  The Journal of physiology     Volume:  564     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-04-13     Completed Date:  2005-08-23     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  631-48     Citation Subset:  IM    
Affiliation:
Department of Biology, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Flow Velocity / physiology
Energy Metabolism / physiology*
Galliformes / physiology*
Muscle, Skeletal / blood supply*,  physiology*
Regional Blood Flow / physiology
Running / physiology*
Walking / physiology*
Grant Support
ID/Acronym/Agency:
AR47337/AR/NIAMS NIH HHS
Comments/Corrections

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