Effect of body orientation on proprioception during active and passive motions.

Abstract

To investigate whether passive and active reproduction of joint position, as well as detection of passive motion (as measures of a subject's proprioception) of the shoulder differ while sitting compared with lying supine. Shoulder proprioception of 28 healthy subjects (age, 22.2 +/- 1.7 yrs, 15 men) was tested. To test proprioception, angular motion (in degrees) for threshold to detection of passive motion and absolute matching error (in degrees) for passive and active reproduction of joint position were measured using an isokinetic dynamometer. As a measure of consistency, the standard deviation per subject and test (threshold to detection of passive motion and passive and active reproduction of joint position) was measured over three trials. The test scores during sitting and lying supine were compared using repeated-measures analysis of variance. No effect of body orientation on threshold to detection of passive motion and passive and active reproduction of joint position scores was found. Significantly larger errors were found during active reproduction of joint position compared with passive reproduction of joint position (F = 58.5; P < 0.01), and subjects were also significantly less accurate during active reproduction of joint position (F = 30.1; P < 0.01). Body orientation does not significantly influence proprioceptive errors or consistency, whereas movement mode (active or passive) does. The significance of these findings is that, depending on the situation or the patient's ability, proprioception tests can be conducted while they are lying or sitting, but movement modes cannot be used interchangeably.