Fig. 6. Bar charts of the average activity of the oblique (A) and intercostal (B) muscles from four dogs during trotting while carrying additional mass distributed over the pectoral and pelvic girdles (filled columns) and centered over the middle of the trunk (open columns). Values are means + S.E.M. The rectified and integrated area of 20 stride cycles was averaged for each dog, and an average value was then calculated from the mean values of the four dogs (N=4). Results are presented as a percentage of values obtained when the dogs trotted without additional mass. Paired t-tests were used to evaluate whether there was a significant difference between the girdle and mid-trunk trials. Muscles with P-values of greater than 0.05 were taken to be not significantly different and are marked NS.