Fig. 7. Approximate lines of action for selected hindlimb muscles of the guinea fowl. Blue solid lines and solid red lines indicate the lines of action for stance and swing-phase muscles, respectively, that significantly increase energy use in response to a load on the distal limb. The lines of action are drawn to show the major actions of the muscles at the joints, and do not necessarily indicate precisely the muscle origins and insertions or to quantitatively indicate the moment arms.