The Concurrent Validity of the Body Center of Mass in Accelerometric Measurement

Accurate estimation of the body center of mass (COM) location has important clinical ramifications in locomotion associated with daily activities of living (ADL). This paper compared two computational estimation methods of COM using an accelerometric measurement and a VICON motion analysis system measurement (established or golden standard), respectively. A convenient sample of four healthy subjects participated. The body COM was measured when the subjects walked on the 6-m long walkway at their self-selected speed for 5 trials. VICON and accelerometer COM data signals were computed by VICON Polygon and trapezoidal double integration methods, respectively and compared to determine the concurrent validity of our COM estimation method. Correlation statistics showed excellent relationship between the two methods (r=0.87, P<0.05), reflecting an acceptable validity. Our results suggest that the COM estimation using the accelerometer method is as accurate as the conventional method and provide clinical insights when designing a portable and inexpensive COM measurement tool for locomotion evaluation.