Fig. 11.

Differences in stance-phase joint moments (A) and positive joint work (B) at the hip, knee and ankle computed using inverse dynamics and using only the GRFs. In A, the moments computed from inverse dynamics (including inertial and gravitational components, solid lines) are compared with the moments estimated from the GRFs filtered at either 15 or 100 Hz (dashed lines). Joint moments are shown for a representative galloping trial (leading limb) from the largest goat (mass 53 kg). Boxplots in B show the corresponding differences in positive joint work determined for five goats (A–E) ranging in mass from 14 to 53 kg. Errors are expressed as a percentage of the joint work computed from inverse dynamics; the median errors and interquartile ranges are from representative trotting and galloping trials at a range of speeds.