The effect of body orientation on shoulder proprioception

Abstract

Objectives. To evaluate the effect of sitting versus lying supine on proprioception of asymptomatic shoulders, and to determine the relationship between shoulder position and movement sense acuity. Design. Repeated measures design. Setting. Laboratory in an educational institution. Participants. Fifteen healthy right-hand males. Method. Tests of passive repositioning and the threshold for detection of imposed movement were employed to examine position and movement sense acuity, respectively. Main outcome measure. For the passive repositioning test, the angular difference between the target and matching positions, i.e. 'matching error', and variance of matching error over repeated trials were calculated. For the threshold test, the amount of joint excursion required to detect correctly the direction of movement, i.e. 'threshold for detection of imposed movement', was calculated. Results. Matching error variance and threshold for detection of shoulder external rotation were significantly lower when subjects were tested in the sitting compared with supine lying positions (p < 0.05). No relationship between shoulder position and movement sense acuity was established (r = -0.16-0.06). Conclusions. Body orientation influences shoulder proprioception. Thus, researchers and clinicians need to consider subjects' body orientation when performing shoulder proprioceptive assessment or rehabilitation. Position sense is different from movement sense. Consequently, position sense may not be used to generalise to movement sense or vice versa. © 2003 Elsevier Science Ltd. All rights reserved.