"The extremely high resolution of this scale requires filtering to produce useful results. Very slight body movement acting on the platform can cause significant noise in A3’s output. This is dramatically apparent in Figure 12’s tracings. The total force on the platform is equal to gravity pulling on the body (the “weight”) plus any additional accelerations within or acting upon the body. Figure 12 (Trace B) clearly shows that each time the heart pumps, the acceleration due to the blood (mass) moving in the arteries shows up as “weight”. To prove this, the subject gets off the scale and runs in place for 15 seconds. When the subject returns to the platform the heart should work harder. Trace A confirms this nicely. The exercise causes the heart to work harder, forcing a greater acceleration-per-stroke."