Introducing timing and history effects in muscular models

Authors: Kosterina, N.K., Westerblad, H, Eriksson, 
Document Type: Conference
Pubstate: Accepted
Year: 2011


Skeletal muscle modeling requires a detailed description of muscular force production. Experiments have been performed on mouse skeletal muscles to give a basis for an improved description of the muscular force production, in particular history and timing aspects. Experimental analysis allowed us to improve the common models of muscle force generation based on the theories of Hill. State-space diagrams were used to investigate timing aspects of force production, in different length variation regimes for fully stimulated muscles. They clearly indicated an exponential nature of the force development in isometric phases of contractions. The time constant of the exponential functions describing isometric force redevelopment after length variations appeared to be in a certain relation with the one for initial isometric contractions for a muscle individual. The muscle activation and deactivation times calculated from the state-space diagrams were in agreement with the generally accepted muscle properties, thereby demonstrating the reliability of the method. The time constants derived from the state-space diagrams and force modification induced by non-isometric contractions were introduced in a muscular model based on Hill equation.