Movie S11.

Mathematical model. This movie shows the contraction of a single half-sarcomere adjacent to six inactive half-sarcomeres (three sarcomeres). The initial length of all half-sarcomeres before activation is 1,500 nm (SL is 3,000 nm). The simulation is ended when the activated half-sarcomere length reaches 750 nm. (Upper Left) Model of cross-bridge activity in the activated half-sarcomere. There are Nmotors myosins within the activated half-sarcomere that can engage with the thin filament during a time interval. This figure shows the state of Nmotors/100 cross-bridges passing through the chemomechanical cycle described in Fig. S7. A motor in state 1, 2, or 3 is represented by a green, red, or blue dot, respectively. For motor i, the displacement from equilibrium of its spring element (εi) is plotted. Over time, as the sarcomere contracts, an increasing number of motors can interact with the actin within the sarcomere. (Lower Left) Time-dependent position of the boundaries between the half-sarcomeres. The A band of the activated half-sarcomere is at the origin, and the boundary at the far right of the plot is the boundary between the first inactive sarcomere and the probe. At t=0, the boundary position is blue, and it shifts to red over time. (Upper Right) Length of the activated half-sarcomere. (Upper Right) Force measured at the probe.