Corresponding to our 12 m/min globally optimal walk is also a much smaller step size of 0.1m than the 0.75m witnessed in humans. Figure 4 also displays how the optimal size of the step increases with increasing average forward velocity; note that all cases yield a roughly linear relationship. The overall trend we observed is very similar to the standard observation that [10] optimal step length for human is directly proportional to the average forward velocity. Since the biped has no foot, how step length should be compared to that of a human is not clear.