Comparison of mechanical power output vT(v) of MUSICO and mass action kinetic models. (A and B) Displayed are comparisons for Huxley (A) and Duke (B) actomyosin cycle. Duke comparisons of the power output with commonly used rate constants are shown as solid lines and closed symbols, whereas the power output with original constants (Duke, 1999) are shown as dashed lines and open symbols. Power output, vT(v), is in atto Watts (aW) per myosin filament. The observed velocities at peak power at ∼v_max/3 are shown as vertical blue dashed lines. Duke velocities at the peak power are shown at its v_max/3 as a green dashed line. Similarly, the velocities at the peak power predicted by all three models with Duke original constants (Duke, 1999) are shown as a black dotted line.