Figure 1.

Photo of the experimental set-up showing an example of forward Step Execution Test being performed under during single task conditions (left). Example of step execution data (right). Fy = Ground reaction forces (shear forces) in antero-posterior direction. Fz = Vertical ground reaction forces, COPx = Mediolateral center of pressure, N = Newton, mm = Millimeter. The following events are marked with X; Tap cue (C); Initial deviation of COPx (A); Foot-off (FO); Foot contact (FC). Note that the tap cue is detectable in any of the signals. See text for further details.