Fig. 3. Blood flow (mean ± s.e.m., N=6) to the muscles that showed significant changes in flow when guinea fowl ran with distal limb loads totaling approximately 5% of body mass. Open bars, control values for unloaded running at 1.5 m s^-1; shaded bars, the loaded values. Muscles are grouped into those active during swing and stance as indicated by EMG activity, previously measured during unloaded running. The FT is grouped with the swing-phase muscles under the assumption that all of the increase in flow due to a load on the distal limb is due to swing-phase metabolic activity (see text). Abbreviations are defined in Table 1.