Fig. 6. Box-and-whisker plots of net mediolateral impulse for each substrate and extremity group. The line in the middle of each box plot represents the median; each box and each whisker corresponds to a fourth of the data; asterisks designate outliers; circle denotes extreme outliers. Positive values indicate a medially directed limb force [laterally directed substrate reaction force (SRF)], and negative values indicate a laterally directed limb force. Substrates were significantly different (N=75, P<0.00001), but there were no differences between limbs within substrate groups.