Footnotes

1. Previous studies have shown that lower extremity loading on the order of 1-2% of body weight can have subtle effects on gait. For the lightest child studied here, the gait monitor was approximately 0.8 % of body weight. For most 6 and 7 year olds (15/20) and all of the oldest children, the monitor was less than 0.5 % of body weight. Thus, a very small loading effect cannot be excluded in the 3 and 4 year olds. However, it seems unlikely that this influenced the comparisons between the two older groups, where as shown below, there were still significant age-related differences.