Fig. 7. Bar charts of the average activity of the serratus ventralis and deep pectoralis muscles from three dogs during trotting while (A) carrying additional mass divided between the girdles or over the mid-trunk and (B) while running uphill and downhill. 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 three dogs (N=3). Results are presented as a percentage of values obtained when the dogs trotted without additional mass (A) or trotted on the level (B). Paired t-tests were used to evaluate whether there was a significant difference between the girdle and mid-trunk trials (A) and between the slope and level trials (B). Muscles with P-values of greater than 0.05 were taken to be not significantly different and are marked NS.