Regensburg 2013 – scientific programme
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BP: Fachverband Biologische Physik
BP 22: Biomechanics (joint focus session with jDPG)
BP 22.4: Talk
Wednesday, March 13, 2013, 16:15–16:30, H6
The muscle's force-velocity relation derived from a basic principle — •Michael Günther1,2,3, Daniel Haeufle1,2, and Syn Schmitt1,2 — 1Universität Stuttgart, Institut für Sport- und Bewegungswissenschaft, Germany — 2Stuttgart Research Centre for Simulation Technology (SimTech), Germany — 3Friedrich-Schiller-Universität, Institut für Sportwissenschaft, Germany
In 1938, A.V. Hill extracted from heat and force measurements on frog muscles that the muscle's concentric force-velocity relation is a hyperbola. In 1957, A.F. Huxley published a model that could approximate the Hill relation from assuming eight microscopic parameters describing partly cross-bridge geometry and partly transition rates for cross-bridge attachment and detachment. Other Huxley-type models, using an increasing number of parameters, have been developed since then. In this presentation, we outline a very reduced set of assumptions that is sufficient to derive the Hill relation from the force equilibrium within a simple macroscopic arrangement of mechanical elements and very few further assumptions about the properties of these elements, all based on physiology. With just three elements, incorporating one force-dependent damper, just four mechanical parameters are needed to find a hyperbolic force-velocity relation. A most recent version of our model including a second damping element can even well explain the heat rate-velocity relation, assuming six parameters. From our model, it can be concluded that it might be erroneous to presume that using the isotonic condition guarantees a direct experimental determination of the properties of the active muscle part.