Measurements of postural stability: development of a force platform and some excitation systems.

Technical data are given for the construction of a low cost transportable force platform to measure postural stability. The measuring elements in the platform are placed between two rigid metal plates to give information about the movements of the center point of force of a standing subject. The system utilizes a microcomputer for data collection, and data analysis routines are used to calculate the movement of the center point of force. Postural perturbation was excited with a vibrating platform, a low frequency noise source and a vibration stimulator for the calf muscles.