Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Coupled Problems in Biological Systems (Focus Session)

BP 7.2: Vortrag

Montag, 7. März 2016, 11:45–12:00, H45

A basic mechanical model of muscular contraction — •Michael Günther, Daniel F.B. Haeufle, and Syn Schmitt — Universität Stuttgart, Institut für Sport- und Bewegungswissenschaft

There is a rich history of quantitative experiments on muscle contraction. Mainly two mathematical approaches are applied to disentangle this hairball. First, A.V. Hill (1938) observed a fibre's steady-state force-velocity relation to be a hyperbola. Later, A.F. Huxley (1957) suggested a mathematical model based on cross-bridges making filaments slide. Using eleven model parameters, Huxley could reproduce in 1973 Hill's relation including its modification from 1964. However, both approaches are not explanatory in a sense that they derive, e.g., the force-velocity relation from basic, physical principles and laws. This led us to ask: what mechanical structure can explain skeletal muscle contractions? As a possible answer, we have worked out a basic mechanical model that can explain, by a force equilibrium between four elements, altogether six characteristic relations of both steady-state and non-steady-state muscular contractions at once. Compared to modern Huxley-type models, the number of parameters is dramatically reduced: we need just six parameters in common plus another two for the steady-state and another three for known microscopic force-length relations specific to non-steady-state responses. We suggest therefore our reduced model to be a promising alternative for advancing causal understanding of the relation between structure and function incorporated into the skeletal muscle machinery.