Falls happen when the center of mass of body is outside of its base of support and the recovery of the center of mass back to the base of support failed. Balance ability is an essential ability needed for humans\u27 daily routine activities. Improving balance ability should result in a better and more convenient way of living. There are various factors influence on balance ability. The focus of this paper is to investigate which factors have the greatest effect on balance. Balance ability is measured by deviations of center of pressure in both x-direction (side-to-side) and y-direction (front-to-back) with the age, height, body mass index, and location of body center of mass. Coordinates of subject\u27s joints were tracked and recorded by a motion capture system with three cameras and then were used to calculate the coordinates of segment\u27s mass center. The coordinates of whole body mass center were determined using the weighted segmental method. The trajectories of the center of pressure were tracked and recorded by a Wii balance board under five standing postures and slow sway movement along x-direction (side-to-side) situations. The information obtained from the center of mass and the center of pressure data analysis may assist with fall prediction and prevention. With a basic training on system operation, laypersons may use this affordable low cost system at home as an exercise tool to improve balance capability and reduce fall risk factors
