CALIBRATION OF MEASURED CENTER OF PRESSURE OF A NEW STAIRWAY DESIGN FOR KINETIC-ANALYSIS OF STAIR CLIMBING

A stairway that allows the collection of kinetic data is essential fbr biomechanical studies on stair climbing. There is a need to validate the measured center of pressure (COP) on the surface of a stair in ord er to verify the accuracy of the calculation of joint kinetics. The pu rpose of this study was to validate a new stairway design for kinetic analysis of stair climbing through a calibration and error analysis of the COP obtained from this system. The new stairway design allows the collection of kinetic data for multiple steps without any constraint to foot placement. Known vertical forces were applied to known locatio ns on the surface of each stair and each force plate. Multiple regress ion analyses were conducted to determine the distribution pattern of t he error in the measured COP. It was found that the error in the COP w as a function of location on the stair or force plate. The magnitude o f the vertical force had no significant effect on the error in the mea sured COP. The distribution pattern of the error in the measured COP o n the force plates used in this study matched the results in the liter ature. A healthy female subject was used as the subject in a stair cli mbing test. The error in the measured COP had a significant effect on the calculated joint resultant moments, especially the abduction-adduc tion and internal-external rotation moments. The correction of these e rrors should make the kinetic calculation in stair climbing more accur ate. Copyright (C) 1996 Elsevier Science Ltd.