The purpose of this study was to investigate the effect of a forward bilateral pushing movement on postural control in a situation where known, unknown, and unpredictable perturbations may be induced. Participants stood upright and voluntarily pushed a handle with both hands. In the first task, the handle was free to be moved by the participant (perturbation; movable task) and in the second task, the handle was locked (stationary task). For each task, body displacement and observed applied force were recorded. Anticipatory postural control adjustment plays a vital role in body stability; however, in contrast to its role in maintaining stability, adjustment can generate a restricted voluntary movement because motor programming selects a postural control that gives priority to body stability over the target movement.

No abstract