Figure 3

Error bar plots of step width variability by subject group and flooring condition. Step width variability was not affected by gait speed but differed significantly by subject group (p<0.0001) and non-significantly by flooring surface (p=0.0066) primarily due to a doubling of step width variability in older females on the visible obstacle surface. While the flooring surface effect did not reach the threshold of significance (p<0.0031) when data were coded for all three surface conditions, when the data were recoded to test for the effects of obstacle visibility (visible obstacles=1 and both other conditions=0), then step width variability was significantly (p<0.0023) increased by obstacle visibility.