Fig. 6. Interspecies variations of V_o and P_o. (A) Relationship between maximum shortening velocity V_o (expressed in µm h^-1 s^-1 for correct comparison among species) and body size. A regression line for slow fibres was obtained by fitting the experimental data with the scaling equation y=ax^-b; the parameters were a=3.309±0.614 and b=0.192±0.013. (B) Values of isometric tension P_o measured in various fibre types in five animal species. Statistically significant differences were found for slow fibres (mouse and pig different from all other species) and for 2B fibres (pig different from all other species). Data for mouse, rat, rabbit and man from Pellegrino et al. (2003).