Fig. 9. Iso-probability contours, derived from the probability distributions in Fig. 8, emphasise the remarkable similarity of scratching movements made under different loading conditions (black, unloaded; red, 142 mg load on the proximal femur; green, 142 mg load on the distal femur; blue, 142 mg load on the distal tibia). The insets show normal distributions to indicate the region of the distribution enclosed by the corresponding iso-probability line for 10, 20, 50, 75 and 90% levels. Black triangles mark the target sites; black squares mark the start postures, and coloured circles mark the corresponding centres of probability density. Number of trials as in Fig. 6.