Comparison of body flexibility between the MR-DF, MR-LF, and MR-LF-S designs.  (A) Foot flexion angle (θf), as a function of actuator magnet orientation (θa) for half-robots at x = 0, ya = 11 cm. The amplitude of data sets indicates the foot’s flexibility. (B) Images of half-robots at their maximum (left) and minimum (right) foot flexion. Arrows on MR-LF-S images point to where the foot contacted the compartment.