A comparison of kinematic recording instruments.

Kinematics, the study of motion, is employed in numerous biomechanics and human performance investigations. The types of instrumentation used in these studies vary at fundamental technical levels, making it difficult to relate results from studies carried out at different laboratories using different instrumentation. A project was designed to compare two commonly used types of kinematic recording techniques, i.e., the 6 df electromagnetic tracker system and the video motion analysis system. A four-level testing and comparison method was conducted involving static and dynamic inanimate objects, as well as human subjects under static and dynamic conditions. It was demonstrated that for rigid body inanimate objects the two systems produce nearly identical values under stationary conditions and are comparable under moving conditions. The systems show only trivial discrepancies in static human body measurements, and perform in qualitatively similar ways on human motion.