This work is concerned with the biological functioning and mechanical behavior of muscles and tendons. A general three-dimensional continuum constitutive model for the mechanical behavior of skeletal muscles and tendons when the materials are subjected to finite strains is proposed. Muscles and tendons are considered as ccomposite materials that consist of fibers, connective tissues, and biofluids surrounding the fibers. The model accounts for all the essential information about the microstructure of the materials. Also, it is constructed in such a way that different material properties of...