Fig. 2.

Stick-figure animation sequence of a representative (a) feet-forward faller and (b) splits faller in responding to a slip induced in gait. The solid and dashed lines, respectively, indicate the right and left sides. The triangle is the starting position of the right heel at right foot touchdown. The five frames on each panel respectively correspond with the instants of the right foot touchdown (RTD), left liftoff (LLO), left touchdown (LTD), the middle frame between LTD and fall, and the instant of fall. Also shown is the definition of the heel-to-heel distance at fall instant.