All three dynamic tests require subjects to shift their COG. The first dynamic test involves rhythmic weight shifting side to side to 50% of the LOS at 3-second then 2-second pacing. Subjects are instructed to match the timing and movement of a bail on the screen by shifting their body weight side to side to target lines denoted on the screen. The second test is similar to the first except movement was now in an anterioposterior direction. Data reflecting the average magnitude of the movement path (expressed as a percentage of the LOS) are produced from six trials at each pace for each movement direction. The absolute error relative to the targets (set at 50% of the LOS) is calculated by subtracting 50 from the score obtained (50% indicating perfect execution) and recording it in absolute terms.