Figure 2. Initiation of the swing phase as a function of the contralateral step cycle.

The horizontal axis represents the time in the left step cycle, which was divided into eight different bins, four for the swing phase and four for the stance phase. The first bin begins at the time of left toe off and the last bin ends at the same event. In response to rapid extension of the right hip, swing phase was most often initiated when the contralateral leg was in the stance phase or late swing phase