Team University of Dayton Engineering & Safety Lab No. 16: Measuring Balance!

If you’ve participated in one of our studies, we probably asked you to stand on something called a balance plate. The balance plate that we use in the lab looks like a scale or a Wii Fit. Since human balance is a complex system, clinicians and researchers have historically had difficulty measuring it. The balance plate overcomes this challenge through the use of sensors called load cells.


When a test subject steps on the plate, the load cells measure vertical force and the movement of the subject’s center of pressure (kind of like your center of gravity). Generally, we conduct tests that last 30 to 90 seconds.

This gives us objective and accurate measurements of medial-lateral (left-right) sway and anterior-posterior (back and forth) sway. This data goes directly to a computer program that graphs the data. The data can be represented a few ways, and the picture to the right shows a common representation of sway.

If the subject had absolutely no sway, there would just be a red dot in the center of the graph. However, everyone has some kind of circle or ellipse. In other words, no human being is perfectly balanced. In fact, having just Yellow circle represents the body’s center of pressure (COP), and red lines show the path that the COP took as the subject stood still. She swayed about 1/2” in each direction