Fig. 5.

Hip muscle moment arm predictions for (a) ADD1, (b) ADD2, (c) ISTR, (d) ITBa, (e) ITBp, (f) PIFE, (g) PIFI2, the muscles for which the sensitivity analysis was performed, for a range of hip flexion/extension angles in Lesothosaurus. A positive hip joint angle (x-axis) indicates hip extension (femoral retraction), while a negative hip joint angle indicates hip flexion (femoral protraction), as shown by the small images of the pelvis of Lesothosaurus in the left lateral view along the x-axis of each graph. A negative moment arm (y-axis) for flexion/extension is a moment arm for flexion; a negative moment arm for abduction/adduction is a moment arm for abduction; a negative moment arm for long axis rotation is a moment arm for medial rotation. FlexExt, flexion/extension; ABDADD, abduction/adduction; LAR, long axis rotation. SA indicates the results of the sensitivity analysis in a–f; CLI indicates the results using the alternative insertion for PIFI2; VO indicates the results using the alternative origin for PIFI2 in g (see text for details).