Learning Objectives:

1. Describe the conceptual distinctions among the four center-of-pressure sway area metrics—rectangular, 66% effective, 95% ellipse, and convex hull—which derive from the same COP data but use different computational approaches. 2. Analyze how each sway area metric reflects changes in postural control across progressive visual disruption and evaluate its ability to detect subtle alterations in single-leg postural control. 3. Justify the selection of sway area metrics when designing sensory-organization assessments or single-leg balance evaluations that manipulate visual feedback and explain why all metrics may be adequate under extreme visual conditions whereas the convex hull area provides a particular advantage under partial visual occlusion.

Keywords: Posturography; Postural sway area; Postural control