Figure 2.

The effects of locomotor speed on muscle force, stress and work. (a) Average maximum force for the LG and MG of guinea fowl walking at 0.5 m s⁻¹ (black) and running at 2.0 m s⁻¹ (grey). (b) Average stress (force/PCSA) for the LG and MG of guinea fowl walking at 0.5 m s⁻¹ (black) and running at 2.0 m s⁻¹ (grey). The numbers (with arrows) indicate the increase in (a) force and (b) stress with an increase in speed. (c) Average mass-specific work for the LG, pMG and dMG of guinea fowl walking at 0.5 m s⁻¹ (black) and running at 2.0 m s⁻¹ (grey). The data are from four individuals and the bars represent the mean±s.e.m. ^*p<0.05 for differences in speed.