Fig. 4
From: Age-related changes in postural control in older women: transitional tasks in step initiation
Median value of velocity of COP and standard deviation of COP (minimum, maximum marked as error bars) in the four conditions (1nd and 3rd phase) among groups A, B, and C. The horizontal bars indicate statistically significant differences within the groups (Friedman ANOVA repeated measures with the post hoc test). Abbreviations: flat – unperturbed crossing; obstacle – perturbed crossing