Fig. 1

a Diagram depicting experiment setup and a subject preforming crossover cut (left top) and sidestep cut to stair ascent transitions (right bottom) using the left (trailing) leg, sidestep cut (right top) and crossover cut to stair ascent transitions (left bottom) using the right (trailing) leg. Auditory cue in unanticipated transitions was given at the initiation of single-leg support of the leading leg (first trailing leg toe-off). Grey dot on the walkway indicates the transition point. b Diagram depicting the 8-segment human body model and the direction of frontal-plane angular momentum