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Host: Greg Sawicki, Ph.D.
Summary Sentence: A Physiology Brownbag Seminar
Full Summary: No summary paragraph submitted.
Thomas RobertsThomas Roberts, Ph.D.
Department of Ecology and Evolutionary Biology
Brown University
Abstract
Elastic structures within muscles have the potential to store and recover energy during movement, potentially enhancing muscle performance. Intramuscular elasticity is often modelled (e.g., in Hill-type models) as a spring element parallel to the contractile element. Such arrangement implies that intramuscular springs are engaged only at long muscle lengths, and only when fibers are lengthened, predictions that are generally supported by measurements of passive muscle stiffness. Because most studies suggest that muscles operate at relatively short lengths during locomotion, and often do not lengthen, the role of intramuscular elasticity has generally been assumed to be limited. Recent work in our lab has focused on an alternative construction of a Hill-type model that includes the deformation of muscles in three dimensions. Model and experimental data predict that in pennate muscles, intramuscular springs will cycle elastic strain energy in virtually all contractions, regardless of fiber length or length trajectory, due to deformation of the muscle off-axis to the fiber line of action. We hypothesize that the collagenous extracellular matrix of muscles acts as a spring to perform functions that have previously been assigned only to in-series tendons, including the cycling of elastic energy during running, and the amplification of muscle power output during jumping.
About the Speaker
Tom Roberts is a professor in the department of Ecology and Evolutionary Biology at Brown University. As a comparative biomechanist, he exploits animal diversity to investigate the link between muscle function and movement. A particular focus of his work has been the central role that elastic mechanisms play in a wide range of movements, in particular how tendon elasticity interacts with the contractile properties of muscle to influence the energetics and mechanics of locomotion. Recent work in his lab focuses on the role that elastic structures within muscle, such as the collagenous extracellular matrix, store and recover energy associated with muscle shaped changes that occur during contractions.
Physiology Brownbag Seminars
The Physiology Group in the School of Biological Sciences hosts Brownbag Lunchtime Seminars twice a month on Wednesdays at noon in room 1253 of the Applied Physiology Building located at 555 14th Street NW, Atlanta, GA 30318. You are welcome to bring a lunch and join us as we ruminate with us on topics in Physiology! A full listing of seminars can be found at http://pwp.gatech.edu/bmmc/seminars/.
