Stepping dynamics of HMM-myoV and FLB-myoV. Displacement vs. time traces for HMM-myoV captured at 60 fps (A), during a Vfast period captured at 30 fps (B) and two different traces one of which shows a period of dynamic stall during a Vslow period captured at 30 fps (C) for FLB-myoV. Step size distributions and their mean ± S.E. of HMM-myoV (n = 290) (D), during Vfast periods for FLB-myoV (n = 266) (E), and Vslow periods for FLB-myoV (n = 235) where the distribution was fitted (R2 = 0.94) by the sum of three Gaussians (F). Step lifetime frequency histograms for HMM-myoV (G), for steps during Vfast (H) and Vslow (I) of FLB-myoV with forward steps (open circles) and backward steps (closed circles) as indicated. The stepping rate (kstep) is the exponential decay constant ± S.E.M. Conditions: 25 mM KCl, 1 mM ATP.