“…Studies of the control of motor behaviors such as locomotion, handwriting, and speech often reveal developmental trends of decreasing variability in both temporal and spatial parameters of movement and increasing velocity of movement with maturation (6,8,9,14,16,18,20,23,24,27,29,31). The development of locomotion is also characterized by a physical scaling principle evidenced by a linear increase in step length as limb length increases (2,18,29,30,33).…”