• Veit WANK


A mathematical model for description of the time course of muscle contractions has been developed by investigations on isolated muscles (animal experiments). This model can be used to describe several types of contractions. Concentric muscle work was subdivided in three partial processes overlapping each other: - the activation process (characterized by the velocity of force development) - the shortening process - the process of force decrease, which is due to the increasing overlap of filaments at the end of contraction. Each process could be described by a separate function. The complex model equation is a multiplicative connection of these function terms. The equation entail seven free parameters representing physiological qualities of the investigated muscles. The parameter values can be estimated by fitting the function to the F(v(t))-curve of the muscle contraction (see right figure: contraction of m.triceps brachii during arm extension). The calculation of muscle forces and contraction velocities during human elbow extension is based on a geometrical model of the arm extensor system (left figure). Needed individual anatomical data were estimated by a special measurement procedure. The parameter values call be used to monitor changes ~n strength fitness achieved by special training protocols and to yield information about the physiological processes involved.