Reliability of an optoelectric system to measure elbow kinematics

Motion analysis of the upper extremity during functional activities has only recently become more accessible. An optoelectric system (WATSMART) was subjected to testing using first a calibration dummy and then human subjects. The mean differences between the system calculated angles and those measured with potentiometers on a calibration dummy were less than 1.6° in all three planes. The test-retest reliability of the system when measuring elbow motion of human subjects yielded acceptable repeatability for measurement of functional activities. Calculation of the least significant difference found that minimum differences from 4 to 14° in flexion and from 10 to 19° in rotation can be detected using the reported set-up and protocol.