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Comparison of force and stiffness in normal and dystrophic mouse muscles
Author(s) -
Gordon T.,
Stein R. B.
Publication year - 1988
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880110804
Subject(s) - isometric exercise , muscle stiffness , stiffness , connective tissue , stimulation , anatomy , muscle contraction , contraction (grammar) , chemistry , troponin , biophysics , materials science , medicine , endocrinology , biology , pathology , composite material , myocardial infarction
Isometric force and stiffness of fast‐ and slow‐twitch muscles of affected and normal mice of the 129/ReJ dy/dy strain were studied at rest and during active contraction at a variety of lengths. Dystrophic muscles developed less force in response to stimulation, but the resting stiffness was not reduced as much, particularly at long muscle lengths. This is consistent with the replacement of muscle fibers by connective tissue that is considerably less elastic. When second and third stimuli are superimposed on the rising phase of a twitch in a normal muscle, a less‐than‐linear summation of force and stiffness generation (early depression) is followed by a more‐than‐linear summation (later facilitation). Dystrophic muscles showed a smaller early depression and a greater later facilitation of force and active muscle stiffness. Many of these phenomena can be predicted from a simple model of Ca 2+ release and binding to troponin.