Mechanics of muscular organs

A continuum theory for predicting the stress and deformation in muscular organs is formulated. It is shown how the experimentally determined stress-strain law for individual muscle fibers may be incorporated into a general continuum theory for the muscular organ as a whole. The behavior of individual muscle fibers is described by Hill's model in which a contractile element is arranged with a series elastic element and a parallel elastic element. The stress tensor for the organ is decomposed into the sum of two terms—one representing the active contraction of the muscle fibers, the other denoting the remaining passive stress.