Figure S18.

Changes in twitch tension predicted by the five-state model for change in ${\mathit{k}}_{\mathbf{+}\mathbf{H}}$ up to ±50% from those used in Fig. 3 (dark green line), denoted as orig. ${\mathit{k}}_{\mathbf{+}\mathbf{H}}\mathbf{.}$ The main effect of changes in $k_{+H}$ on the tension responses are displayed in modest changes in the peak tension, resting tension, the rate of tension rise, and the rate of relaxation. For all values of $k_{+H}\mathrm{,}$ the rate of relaxation is about twofold slower than that observed.