Fig. 5. Measured AP recovery (symbols) compared to the volume averaged model of AP recovery (solid line) in small (A) and large (B) dark fibers. The dotted line indicates the resting concentration. In the model, the myosin ATPase was activated long enough to cause a decrease in AP that was comparable to the measured data. (C,D) Three-dimensional graphs show the temporally and spatially resolved concentrations of AP for small (C) and large (D) dark levator fibers during a contraction-recovery cycle. This model output was generated using parameters in Table 2. Note the absence of concentration gradients.