Comparative Sensitivity Analysis of Muscle Activation Dynamics

Figure 1

Relative sensitivities with respect to the three parameters in the simplified formulation (22) of Zajac’s activation dynamics (1). Parameters: stimulation (see (25): solid line), activation time constant (see (26): dashed line), and initial activation (see (27): dash-dotted line). Note that is negative, but for reasons of comparability we have plotted its absolute value. Parameter values are , , and . Because ODE (22) for is equivalent to Hatze’s ODE (2) for the free -ion concentration, , we can identify the sensitivity of with that of .