MEASUREMENT OF FOREARM ROTATION - THE TECHNIQUES, AND ITS REPRODUCIBILITY AND VALIDITY

Forearm rotation is a point of interest in the study of human movement. For the most part, earlier methods for determining this joint rotation could be applied only in restricted situations. In this paper, a new technique is described, which involves the use of a three-dimensional opto-electronic motion registration system. With only two cameras, the supination angle in almost every position can be determined. A bracelet is attached to the subject's forearm and fixed to the radius. Wrist points are defined in relation to this bracelet (in its local coordinate system). The properties of the bracelet allow the motion-registration system to calculate its position in the global coordinate system. Given the position of the bracelet, the shoulder, and the elbow, the rotation angle can be determined. The reproducibility (error less than 2-degrees) of and validity of the technique are also discussed.