DYNAMICS OF POSTURE IN 3-YEAR-OLD AND 5-YEAR-OLD CHILDREN AS A FUNCTION OF TASK CONSTRAINTS

The postural dynamics of 3- and 5-year-old children were examined unde r task constraints of one- and two-leg stance with and without vision. Force platform measures showed that motion of the center of pressure increased as the task constraints changed from bipedal to one-legged s tance and vision available to no vision, and that this performance dec rement was enhanced in the 3-year-old age group. Videotape analysis of the movement of the torso and limbs during the postural task showed t hat the children attempted to accommodate the decreased stability of t he more difficult task conditions by introducing the control of more b iomechanical degrees of freedom into the postural action, but systemat ic compensatory movement pattern strategies were only evident in the o lder 5-year-old group. The findings are consistent with the notion tha t compensatory movement strategies for the recovery of postural stabil ity under more difficult task constraints are reflections of experienc e in exploiting the dynamics of the perceptual-motor workspace.