Fig. 4. Comparison of the model output to the experimental results across a range of stimulation conditions with activation constants optimised to fit a single stimulus condition (Fig. 3). Length, force, energetic output, activation and contractile component velocity are compared between the model output (dotted blue lines) and the experimental results (solid blue lines). The convention for these figures is the same as for the single condition in Fig. 3, with the red lines indicating the modelled energetic output for the experimental data (energy plot), the estimated experimental activation level (activation plot) and the MTU velocity [contractile component (CE) velocity plot]. The comparison is made at three different cycle frequencies: (A) 5 Hz, (B) 1.25 Hz and (C) 0.71 Hz, with varying duty cycle and phase.