Figure 1.

GRFs and duty factor in monitor lizards. (a) Caudal displacement of the horizontal body centre of mass (electronic supplementary material, figure S4). Average forelimb (b) and hindlimb (c) GRFs of monitor lizards recorded on a force-plate (e) for vertical (Z, red), cranial–caudal (X, yellow) and medial–lateral (Y, purple) directions. (d) Total GRF impulse varied with body mass and relative speed. (f) Relative proportion of X, Y and Z impulses varied with body mass and fore versus hindlimb. Duty factor increased with body mass (g) but decreased with relative speed (h) and was higher for the hindlimb (green triangles) than the forelimb (blue circles). Shading in (g,h) indicates 95% confidence intervals (a,d,g,h) are depicted on log scales.