Do body proportions influence musculoskeletal design?
Adaptive differences in limb proportions have a predictable and significant effect on the orientation of limb segments at mid-stance at walking speeds, while the limb proportion effect is more equivocal at touch-down and mid-stance. The effect of limb proportions on joint moments and the effective mechanical advantage of extensor muscles is most apparent when the differences in proportions are sufficiently large. Animals with longer limbs tend to use more extended joint postures than those with shorter limbs, presumably moderating the larger mid-stance bending and joint moments they would otherwise incur. The observation that forelimb joint moments were lower in longer-limbed primates corresponds well with the scaling of cross-sectional properties observed by Polk et al. (2000). Humeral polar moments of area, which should reflect an average resistance to bending (Schaffler et al., 1985), and cortical areas that resist compressive and tensile loads both scale isometrically when regresse
