Figure S2.

Effect of the five-state cross-bridge model rate ${\mathit{k}}_{\mathbf{-}\mathbf{A}}^{\mathbf{o}}$ on relaxation of twitch tension in isometric half-sarcomeres (IoSarc.). The simulation, with parameters obtained from fits of isometric half-sarcomere tension at 27.2°C (Fig. 3), shows slow relaxation (dark green line). An additional increase of $k_{-A}^o$ by ∼17-fold significantly increases the rate of relaxation (green line and arrows), but it is still insufficient to reach the observation (dark gray line). The superscript o is omitted from the figure display for clarity.