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Updated: May 29, 2026
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Experimental Methods to Study Human Postural Control
Published on: September 11, 2019
Exploratory behavior during stance persists with visual feedback
C D Murnaghan1, B C Horslen, J T Inglis
1School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
Neuroscience
|August 27, 2011
Summary
Postural sway, or body movement, may be an active exploration for sensory information, not a sign of balance problems. This study confirms that increased sway occurs when body movement is stabilized, even with sensory feedback.
Area of Science:
- Biomechanics
- Human Motor Control
- Neuroscience
Background:
- Postural sway, measured by center of pressure (COP) displacements, has been theorized to be an exploratory mechanism for sensory information acquisition.
- Previous studies suggested that external stabilization of the center of mass (COM) increases COP displacements, supporting the exploratory theory.
- Potential confounding factors like sensory illusions or motor drift needed to be ruled out to validate the exploratory role of postural sway.
Purpose of the Study:
- To further investigate the theory that postural sway is an exploratory process for gathering sensory data.
- To eliminate confounding variables such as sensory illusions and motor drift in the observed relationship between COM stabilization and COP displacement.
- To assess the impact of real-time visual feedback (COM or COP) on postural sway during COM stabilization.
Main Methods:
- Participants stood in an apparatus that stabilized their center of mass (COM) without their awareness.
- Real-time visual feedback of either COM or COP position was provided to participants during trials.
- COP displacements were measured under conditions of COM stabilization with and without visual feedback.
Main Results:
- Consistent with prior findings, COP displacements increased when COM movements were externally stabilized.
- These increases in COP displacement persisted even when participants received visual feedback suggesting COM stabilization (COM feedback).
- Awareness of COP position (COP feedback) did not reduce the observed increase in COP displacement during COM stabilization, ruling out sensory illusions or motor drift.
Conclusions:
- The findings provide robust support for the hypothesis that postural sway is an exploratory behavior.
- The results indicate that increased sway is not solely indicative of a failing balance control system, challenging traditional clinical assumptions.
- A re-evaluation of current clinical practices for balance deficits in aging or diseased populations may be necessary if sway is fundamentally exploratory.
