PROPRIOCEPTION DURING MANUAL AIMING IN INDIVIDUALS WITH SHOULDER INSTABILITY AND CONTROLS

Recurrent glenohumeral joint instability is a common orthopaedic probl em. One possible cause of this repeated instability is a lack of neuro muscular control and kinaesthetic sense oi the glenohumeral joint. The purpose of this study was to determine whether there is a deficit in joint proprioception in subjects with recurrent anterior glenohumeral instability as compared with individuals with no previous shoulder pat hology. Subjects were asked to generate pointing movements with their uninjured limb and to match this limb position with the injured limb. Movements of the pointing limb were measured with an optoelectric thre e-dimensional movement analysis system. These movements were performed in three conditions: 1) with lull vision, 2) without vision, and 3) w ithout vision with vibration to the posterior deltoid muscle. For the temporal and spatial measures, there were no significant differences b etween the control and shoulder instability groups. However, the kinem atic data describing arm trajectory formation showed a performance dec rement in the no vision with vibration condition for the subjects in t he shoulder instability group, suggesting that they suffer from a prop rioceptive deficit.