What is the limit of stability (LOS), and how is it used clinically to assess balance?

• A. LOS is the maximum distance a person can shift their center of mass without losing balance or stepping; clinically estimated via forward reach tests or computerized posturography to gauge fall risk and balance capacity.
• B. LOS is the minimum distance the COM must move to initiate stepping.
• C. LOS is the distance between COM and COP at rest.
• D. LOS is the distance the feet can move during stepping without losing balance.

Answer: (D)

The limit of stability is about how far you can shift your body's center of mass within your base of support before you lose balance or need to take a step. It reflects how much sway you can control without changing your support under your feet. Clinically, this is assessed by seeing how far you can lean or reach without stepping, using tests like forward reach or more sophisticated measures from computerized posturography. This distance provides a practical gauge of balance capacity and fall risk.

The description that focuses on how far the feet can move during stepping isn’t LOS; that describes stepping distance or stepping threshold, a different measure of balance strategy. Similarly, the static gap between center of mass and center of pressure at rest isn’t about how far you can lean before losing balance. The LOS specifically captures the maximal voluntary displacement of the center of mass within the base of support before a step or loss of balance is needed.