Balance can be simply understood as an individual's ability to maintain their center of mass over their center of pressure. The graphic below can be used to better understand what measures are being collected during the Balance Scan. This allows for a more technical explanation, but also a more clear understanding of what these measures are and how it relates to what they represent and the trends we see.
The Balance Scan measures a variety of different variables, with some of the most basic ones discussed below. The graphic above is a simple visual representation of a Sway Path of a users Center of Pressure, collected during the balance scan. The results of the Balance Scan that display to the user are based on the Average Resultant Sway Velocity.
Average Resultant Sway Velocity is the average total (resultant) speed (velocity) of sway or movement during the balance scan. The term resultant simply means that this measure is multi-directional, in both the Anterior-Posterior (front to back) and Medial-Lateral (side to side) directions. This is measured in m/s.
Mass is the average force applied during the stand-still period. This is calculated prior to the balance for a 2 second stand-still period to determine the most accurate measure. Mass is measured in kilograms.
Sway Path is the total distance covered by the center of pressure during the balance Scan and is represented above with the drawing or tracing. We can see above that this path can be split into the Anterior-Posterior and Medial-Lateral planes to understand the direction of sway. The simplest way to understand sway velocity is by simply taking the total sway path (in meters) divided by the total amount of time (20 seconds in this case).
To learn more, check out our article on Balance Testing