REPEATABILITY OF BODY SWAY MEASUREMENTS - DAY-TO-DAY VARIATION MEASURED BY SWAY MAGNETOMETRY

The postural stability of 30 normal subjects in the age range 15 to 64 years was measured on five separate occasions, using the sway magneto metry technique, to determine the day-to-day repeatability of this mea surement technique. On each occasion the pathlength and area enclosed by movement of the hips in a horizontal plane were measured over two 3 0 s periods with eyes open and eyes closed, with subjects standing on a firm base. Day-to-day repeatability had a standard deviation of 14% for pathlength and 42% for area. Neither the age nor the sex of the su bject had any demonstrable effect on the results.