Fig. 3. Integration of five levels of analysis of stance phase dynamics during hindlimb locomotion in alligators. (A) Dynamic phases of stance. (B) Torsional moment of the ground reaction force acting on the femur; illustrates torsional moments on the right femur as viewed from the acetabulum. (C) Three-dimensional ground reaction forces (top, vertical; middle, fore-aft; bottom, mediolateral) in body weight units (BWU). (D) Mean footfall patterns; R, right; L, left; H, hindlimb; F, forelimb. (E) Mean hindlimb kinematics. (F) Mean electromyographical patterns for 16 hindlimb muscles, constructed from the data in Table 1 and Gatesy (1997; indicated by ^*). All of the data (details in Materials and methods) are from alligators of similar size, moving at the same speed (0.146 m s^-1), posture (femur adducted 51-60°), and gait (duty factors 0.70-0.73). Vertical green bars delineate the three dynamic phases of limb function (from A) during the stance phase: limb loading, support and propulsion and limb unloading, described in text.