DEVELOPMENT OF THE UPRIGHT POSTURAL SWAY OF CHILDREN

From 1988 to 1992, 1188 children (576 boys and 612 girls) three to 11 years old were studied using the Stasio-analyzer to clarify developmen tal change of upright postural sway. Developmental change in the conta ct surface area of the sole, the coefficient of variation for the cont act surface area, total sway area, total sway path and position of the centre of gravity were analysed. The contact surface area increased m arkedly between the ages of three to five and of seven to nine years, and increased slightly between six and seven years. Age six to seven y ears is proposed as a turning point of plantar arch formation as regar ds change in the contact surface area of the sole. Upright postural sw ay decreased markedly between the ages of three to five years and then slowly after age six. Boys under ten years swayed more than girls. Th e centre of gravity of the foot in children standing upright shifted t owards the toes with increasing age: its distance from the heel was ab out 36 per cent of the foot length at age three to five years and 42 p er cent at 11 years.