Figure 3.

Muscle indices of relative power, joint torque, and joint rotational velocity of rabbit muscles. All architectural properties are normalized to body mass (M _b) to standardize the presentation of data. (a) Normalized PCSA as a function of normalized fascicle length (L_F). PCSA is scaled to ${\mathrm{M}}_{\mathrm{b}}^{0.67}$ and fascicle length to ${\mathrm{M}}_{\mathrm{b}}^{0.33}$. (b) Normalized PCSA as a function of muscle moment arm (r _m). Values for r _m are scaled to ${\mathrm{M}}_{\mathrm{b}}^{0.33}$. (c) Normalized L_F as a function of normalized r _m. Data points are means, with no error bars shown. Blue data points are adults (> 1.0 kg); red data points are juveniles (< 1.0 kg). Dashed lines divide plots into even quadrants. Muscles that produce high force (large PCSA) and shorten at high velocity (long L_F) are capable of high power output (upper right); large PCSA and long r _m are muscles capable of applying large joint torque (upper right); and long L_F and short r _m are muscles capable of fast joint rotational velocity (upper left). Muscle abbreviations are the same as those in Table 2. h, acting at hip joint; k, acting at knee joint; a, acting at ankle joint.