Fig. 4. Moment arm measurements about the hip and knee joints. (A) Moment arms about the flexion—extension axis of the hip joint in experimental frogs were measured relative to a starting, test position (see text). Values are means ± 1 S.D., N=8. The color scheme is as follows: ADd, dark gray; ADv, orange; CR, brown; GL, yellow; GR, red; ILe, dark green; ILf, light gray; ILi, purple; SA, light blue; STd, black; SM, light green; TFL, dark blue. FLEX, flexion; EXT, extension. (B) Moment arms about the abduction—adduction axis of the hip joint in experimental frogs. ADD, adduction; ABD, abduction. (C) Moment arms about the internal—external rotation axis of the hip joint in experimental frogs. EX, external rotation; IN, internal rotation. (D) Moment arms about the flexion—extension axis of the frog knee joint were measured relative to a test position (see text). Values are means ± 1 S.D., N=6. (E) Moment arms about the flexion—extension axis of the hip in the model frog. (F) Moment arms about the abduction—adduction axis of the hip in the model frog. (G) Moment arms about the internal—external rotation axis of the hip in the model frog. Muscle abbreviations: semimembranosus (SM), gracilus major (GR), adductor magnus dorsal and ventral heads (ADd and ADv), cruralis (CR), gluteus magnus (GL), semitendinosus ventral and dorsal heads (STv and STd), iliofibularis (ILf), iliacus externus (ILe), iliacus internus (ILi), sartorius (SA) and tensor fascia latae (TFL).