Acquisition of upper body stability during walking in toddlers

This study examines the development of head and trunk movements in toddlers as they begin to walk independently. The data are from a longitudinal stud y of 7 infants observed from the onset of walking over a period of 46-80 we eks. Head and trunk rotations were measured in the frontal and sagittal pla nes together with global gait parameters (progression velocity, step cadenc e, length and width, duration of double support phase). The results showed that during the first weeks of walking head and trunk oscillations signific antly decreased, indicating that considerable progress is made in upper bod y stabilization. Dramatic changes in global gait parameters also occurred a t this time. After this first period of rapid changes, gait parameters cont inued the same developmental trend but with slower changes. The close relat ion between gain in head and trunk stability and improvement in walking eff icacy is discussed on the basis of the individual developmental trends. (C) 2000 John Wiley & Sons, Inc. Dev Psychobiol 36: 311-324, 2000.