RELATIONSHIPS BETWEEN ISOMETRIC AND ISOTONIC MECHANICAL PARAMETERS AND CROSS-BRIDGE KINETICS

1, Isometric and isotonic measures have been widely used both to chara cterize muscular contraction in striated muscle and to compare the mec hanical properties of striated muscle types for a wide variety of spec ies. The interrelationship of these measures and their interpretation, in terms of underlying cross-bridge mechanisms, requires clarificatio n. 2, We demonstrate that a strain-dependent three-state model can sim ulate these isometric and isotonic mechanics and offer a unified expla nation for these mechanics in terms of crossbridge kinetics. 3, Our ex ploration reveals the partial view each individual measure of mechanic s provides and emphasizes the complementary insights the various isome tric and isotonic measures give of the underlying cross-bridge kinetic s.