Fig. 1

Schematic representation of the original cross-bridge model with a myosin cross-bridge cyclically interacting with specific attachment sites on the actin filament. In the lower part of the figure is a representative illustration of the asymmetrical rate constants of attachment (f) and detachment (g) that are thought to govern the cross-bridge kinetics. Also shown is the so-called “x-distance” on the top and bottom parts of the figure, which is defined as the distance from the cross-bridge equilibrium position to the nearest eligible attachment site on actin. (Adapted from Huxley [1], with permission)