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Deformation and three‐dimensional displacement of fibers in isometrically contracting rat plantaris muscles
Author(s) -
Savelberg Hans H.C.M.,
Willems Paul J.B.,
Baan Guus C.,
Huijing Peter A.
Publication year - 2001
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1061
Subject(s) - isometric exercise , anatomy , perpendicular , contraction (grammar) , plantaris muscle , deformation (meteorology) , displacement (psychology) , materials science , muscle contraction , muscle belly , composite material , biology , geometry , skeletal muscle , mathematics , soleus muscle , tendon , physiology , psychology , psychotherapist , endocrinology
Abstract In this study, the deformation of different fibers of the rat m. plantaris during “isometric” contractions at different muscle lengths was considered. Because the m. plantaris has an obviously inhomogeneous architecture, its fibers on the medial side of the muscle belly are judged to be shorter than those on the lateral side of it. It was expected that longitudinal deformation of different fibers would vary accordingly. A 3D video analysis of contracting muscle showed that longitudinal strain of fibers as a function of muscle length does not differ between fibers on different sides of the muscle. Apart from longitudinal shortening, the fibers were also displaced laterally during a contraction. The fibers displaced during a contraction in a direction perpendicular to their longitudinal axis. The displacement of the fibers occurred asymmetrically, resulting in a helical deformation of the whole muscle. It is concluded that the asymmetric displacement and the helical deformation must result from transversal forces between the fibers. It is hypothesized that these transversal forces cancel out differences in longitudinal strains that might exist between fibers. J. Morphol. 250:89–99, 2001. ©2001 Wiley‐Liss, Inc.