Crossmodal versus intramodal evaluation of the knee joint angle : A normative study in a population of young adults

Normative data on position sense in the knee joint were obtained from a population of young adults (N = 46, mean age: 22). Kinaesthetic and visual evaluation of the knee joint angle was measured in crossmodal and intramodal matching tasks. In terms of absolute errors, the scores, although similar in both crossmodal tasks, were significantly lower in the unimodal matching task; the subjects' laterality had no significant effects. In terms of signed errors, the scores had opposite polarities between the kinaesthetic-visual and the visual-kinaesthetic tasks; moreover, the kinaesthetic intramodal task showed an obvious laterality bias. The angle reference value was found to affect the magnitude and sign of error variably depending on the task. The smallest errors were observed around the resting position in crossmodal matching, whereas they increased monotonically from extension to flexion in unimodal kinaesthetic matching. The data are interpreted in terms of the underlying physiological mechanisms and psychophysical determinants. Some clinical and sport applications are suggested.