The development of compensatory stepping skills in children

The development of the ability to use the step for balance recovery was studied among twenty-five 9- to 19-month-old children. The children were grouped according to walking experience (4 levels) and exposed to backward support surface translations, 8 cm in amplitude, under 3 velocity conditions: 15, 20, and 25 cm/s. New walkers (up to 2 weeks' walking experience) used the step infrequently and ineffectively in response to threats to balance. Intermediate walkers (1-3 months' walking experience) showed an increasing use of the step and significant improvement in step execution compared with new walkers. Advanced walkers (>3; months' walking experience) experienced no falls throughout the protocol, capturing balance with feet-in-place or step responses under all perturbation conditions. A significant developmental transition in the emergence of the compensatory step occurred between the new walker and the intermediate walker experience levels, that is, within the first 3 months of walking experience. Three to 6 months' experience was required for the development of an effective stepping response. A concomitant change in mediolateral stability paralleled the emergence of compensatory stepping.