| Relative shortening velocity in locomotor muscles: turkey ankle extensors operate at low V/V(max). | |
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MedLine Citation:
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PMID: 17977918 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The force-velocity properties of skeletal muscle have an important influence on locomotor performance. All skeletal muscles produce less force the faster they shorten and typically develop maximal power at velocities of approximately 30% of maximum shortening velocity (V(max)). We used direct measurements of muscle mechanical function in two ankle extensor muscles of wild turkeys to test the hypothesis that during level running muscles operate at velocities that favor force rather than power. Sonomicrometer measurements of muscle length, tendon strain-gauge measurements of muscle force, and bipolar electromyographs were taken as animals ran over a range of speeds and inclines. These measurements were integrated with previously measured values of muscle V(max) for these muscles to calculate relative shortening velocity (V/V(max)). At all speeds for level running the V/V(max) values of the lateral gastrocnemius and the peroneus longus were low (<0.05), corresponding to the region of the force-velocity relationship where the muscles were capable of producing 90% of peak isometric force but only 35% of peak isotonic power. V/V(max) increased in response to the demand for mechanical power with increases in running incline and decreased to negative values to absorb energy during downhill running. Measurements of integrated electromyograph activity indicated that the volume of muscle required to produce a given force increased from level to uphill running. This observation is consistent with the idea that V/V(max) is an important determinant of locomotor cost because it affects the volume of muscle that must be recruited to support body weight. |
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Authors:
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Annette M Gabaldón; Frank E Nelson; Thomas J Roberts |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2007-10-31 |
Journal Detail:
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Title: American journal of physiology. Regulatory, integrative and comparative physiology Volume: 294 ISSN: 0363-6119 ISO Abbreviation: Am. J. Physiol. Regul. Integr. Comp. Physiol. Publication Date: 2008 Jan |
Date Detail:
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Created Date: 2008-01-10 Completed Date: 2008-02-26 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 100901230 Medline TA: Am J Physiol Regul Integr Comp Physiol Country: United States |
Other Details:
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Languages: eng Pagination: R200-10 Citation Subset: IM |
Affiliation:
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Oregon State University, Department of Zoology, Corvallis, OR, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Biomechanics Electromyography Female Locomotion / physiology* Muscle Contraction / physiology Muscle, Skeletal / physiology* Running / physiology* Tarsus, Animal / physiology* Tendons / physiology Turkeys / physiology* |
| Grant Support | |
ID/Acronym/Agency:
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AR46499/AR/NIAMS NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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