BIOMECHANICAL GROWTH LAWS FOR MUSCLE-TISSUE

It is generally acepted that growth of muscle tissue depends in part o n biomechanical factors. However, the precise relationships that gover n mechanically induced growth are not known. This paper uses available data to propose a set of biomechanical growth laws for striated and s mooth muscle. For striated muscle fibers, transverse and longitudinal growth are hypothesized to depend on the active and passive fiber stre ss, respectively. For smooth muscle fibers in arteries, transverse gro wth is assumed to depend on the fiber stress (active behavior is ignor ed), with longitudinal growth depending on both fiber stress and the s hear stress on the endothelium due to blood flow. In both types of mus cle, the rate of growth is assumed to depend linearly on the stresses. Relatively simple models for skeletal muscle, the heart, and arteries are used to show that the proposed growth laws can predict many of th e known characteristics of muscle growth during development and follow ing load perturbations in the mature animal. (C) 1998 Academic Press