Figure 3.

The trajectory of the limb was changed immediately after the initial trip. (A) The trajectory of the knee (tibial head), ankle (lateral malleolus), and foot (metatarsophalangeal, MTP) for the same steps in Figure 2 are shown. (B) An expanded plot of the trajectory of the MTP during late stance and early swing of the Trip 1 and Trip 2 steps are depicted. The solid symbols in (A,B) indicate when the foot touches the trip rod. Note the earlier initiation of the swing phase in Trip 2 than Trip 1 for both sequences.