Position sense testing: influence of starting position and type of displacement.

OBJECTIVE To assess the effect of starting position, target position, and various types of limb displacement on repositioning tests commonly used for clinical evaluation of rehabilitation. SETTING Controlled laboratory environment. PARTICIPANTS Sixteen healthy volunteer subjects. MAIN OUTCOME MEASURE Absolute error, ie, the absolute difference between target and replicate positions. DESIGN Each subject performed four testing procedures consisting of different types of limb displacement (active, passive, and passive during antagonist muscle contraction). For each procedure, horizontal movements were performed ipsilaterally about the right glenohumeral joint from one intermediate starting position (40 degrees ) and two extreme starting positions (0 degrees and 80 degrees ). Four fixed target positions (16 degrees , 32 degrees, 48 degrees , 64 degrees ) were presented for each starting position. The subjects were required to replicate target position after returning to the respective starting position. RESULTS Lower repositioning errors occurred with active displacement procedures compared with passive, and with the intermediate starting position compared with the extreme. Target position, however, had no effect on repositioning errors. CONCLUSIONS Starting position and type of displacement should be considered in interpretations and comparisons of data from clinical studies.