Parameter sensitivity. Analysis of the simulation of an unloaded twitch contraction shown in Fig 6. (A–H) As described in Results, each panel shows how the fit deviates from the optimum as the value of an individual parameter is modified. Confidence limits, defined as the range of parameter values for which the simulated fit remains within 5% of the optimum, are shown above each plot. See Table S4 for details relating to model parameters.