The SELSPOT 3D Motion Measurement System provides accurate measurement data f many kinds of movement. The SELSPOT II camera and MULTILab software package can be used to perform a complete analysis of the data. The camera has a patented photodetector which registers light pulses emitted by LEDS attached to the object being analyzed. Because the LEDs (markers) are sequenced by the system, there is no "guessing" as to which marker went where or which markers were obscured. The electronic system automatically adjusts the light intensity of the LEDs and suppresses ambient light. The camera registers the X and Y coordinates of the signal, digitizes the data, and then sends the data to the computer for analysis and reporting. 3D analysis is possible with two or more cameras. Up to 16 cameras and 120 LEDs can be used. The base sampling rate is 10 kHz -- for example, with two cameras and five LEDs the sampling rate would be 1000 Hz. Resolution is 0.025% of the measuring range; non-linearity of the detector is less than 0.1% of the measurable range. The software also allows input from up to 48 analog channels supporting analog sensors, such as, force plates, EMG electrodes, etc. The data from the camera(s) and other sensors are synchronized by the system. MULTILab is a high-level programming language that performs all of the calculations for angles, velocities, acceleration, moments, etc., and provides customized reports containing all of the information necessary for sophisticated motion analysis. The system is rapid, accurate, reliable, and easy to use.