Fig. 9

Relative optimal fiber length \( {L}_{\mathrm{o}}^{\mathrm{M}} \) in mice and humans. (a) Comparison of relative \( {L}_{\mathrm{o}}^{\mathrm{M}} \) of muscles crossing the hip, knee, and ankle joints between mice and humans. Mean and standard deviation of relative \( {L}_{\mathrm{o}}^{\mathrm{M}} \) plotted in (a) were taken directly from Tables 3 and 4 in [41] and Table 3 in [46] for the muscles of mouse hindlimb and human lower limb, respectively. Each symbol is one muscle. The dashed line is the unity line representing the equal relative \( {L}_{\mathrm{o}}^{\mathrm{M}} \) between mice and humans. (b) Relative \( {L}_{\mathrm{o}}^{\mathrm{M}} \) was defined as \( {L}_{\mathrm{o}}^{\mathrm{M}} \) normalized by muscle belly length, which was the distance from the origin of the most proximal fibers to insertion of the most distal fibers