A three dimensional continuum model of skeletal muscle

Skeletal muscle consists of a nonlinear, anisotropic, fibrous contractile material. Besides, these properties are distributed non-uniformly across the muscle, which itself can have a complex geometry. Traditional models can not predict the actual local behaviour of the muscle, because uniformity and/or simple geometries are assumed. We present a model, which takes into account the active contractile properties using a Distributed Moment approximated Huxley model and the passive tissue with a three dimensional nonlinear anisotropic elastic model. The model is approximated numerically with the finite element method. The main features of the model are illustrated with simulations of an isometric contraction of a geometrically simple muscle for a plane stress and a plane strain situation; Large differences between both situations demonstrate the importance of this type of modelling.