Are increases in COP variability observed when participants are provided explicit verbal cues prior to COM stabilization?

•Increases in COP displacements were observed following stabilization of the COM during stance.•Knowing when and how stabilization would occur did not prevent increases in COP displacement.•The results provide further support for an exploratory role of postural sway.

Previous research has shown that when the COM is stabilized without participant awareness, COP displacements increase. This finding suggests that postural sway under normal conditions may be exploratory and used as a means of acquiring sensory information. However, based on the theory that posture is controlled using internal models, it could be argued that increases in COP displacement reflect errors that arise as the central nervous system attempts to adapt the internal model used to control posture to the new conditions. The current study provided an explicit verbal cue to the participants indicating how and when COM stabilization would occur. Based on evidence suggesting that explicit verbal cues can reduce errors when the dynamics of the task are altered, we hypothesized that when participants were aware of COM stabilization, COP displacements would be reduced. However, we found that anterior-posterior COP displacements increased independent of cueing, suggesting that increases in COP displacements with locking were not the result of an attempt to adapt the internal model of postural control. The results provide further support for an exploratory role of postural sway.