Fig. 3

a Representative trials from a 7-year-old TD child (left column) and an age-matched ASD child (right column). b Representative trials from an 11-year-old TD (left column) and an age-matched ASD child (right column). In general, TD children show an overall COP variability reduction with age at all standing conditions while this developmental change was not observed in children with ASD. The COP time series of the ASD children shows more variability than that of their TD peers. In static stance, the children with ASD showed increased COP variability in both AP and ML directions. In both dynamic postural sway conditions, the children with ASD showed increased COP variability in the directions orthogonal to the target. For better display of the COP time series and postural limitation boundaries, scales on the x and y axes of each child’s plots were adjusted and thus are not consistent across participants. The semi-major and semi-minor axes of their postural limitation boundary were aligned with the force platform coordinate for all images