Towards multi-scale modeling of muscle fibers with sarcomere non-uniformities.
A theoretical framework for studying the collective behavior of a large ensemble of half sarcomeres in a myofibril is presented. The approach is based on transforming the large system of discrete elements (half-sarcomeres) into a continuum for which macro-behavior is dictated by micro-properties. Specifically, we consider statistical properties of the ensemble rather than solving for each degree of freedom. This enables a reasonable computational effort and provides important insights. We demonstrate that such a multi-scale approach is indispensable for studying quantitatively the role of sarcomere non-uniformities in muscle mechanics. Specifically, we illustrate that adopting a model with a non-physiological number of sarcomeres can lead to a non-realistic behavior and therefore to erroneous interpretation. Further, we demonstrate that the new modeling approach provides a suitable platform for addressing controversial phenomena, such as residual enhanced tension, creep, length redistribution, and damage due to eccentric contraction.
Givli
Sefi
S
Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel. givli@technion.ac.il
D000465:Algorithms; D000818:Animals; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008954:Models, Biological; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D009210:Myofibrils / Q000502:physiology*; D012518:Sarcomeres / Q000502:physiology*