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 t arget and replicate positions. Design: Each subject performed four testing procedures consisting of differ ent types of limb displacement (active, passive, and passive during antagon ist muscle contraction). For each procedure, horizontal movements were perf ormed ipsilaterally about the right glenohumeral joint from one intermediat e starting position (40 degrees) and two extreme starting positions (0 degr ees and 80 degrees), Four fixed target positions (16 degrees, 32 degrees, 4 8 degrees, 64 degrees) were presented for each starting position. The subje cts were required to replicate target position after returning to the respe ctive starting position. Results: Lower repositioning errors occurred with active displacement proce dures compared with passive, and with the intermediate starting position co mpared with the extreme. Target position, however, had no effect on reposit ioning errors, Conclusions: Starting position and type of displacement should be considere d in interpretations and comparisons of data from clinical studies.