Variation in shoulder position sense at mid and extreme range of motion

Objective: To determine the effect of different joint positions on position sense of asymptomatic shoulders. Design: Repeated-measures design. Setting: Laboratory in an educational institution. Participants: Thirty-four asymptomatic, right-handed men. Interventions: The ability of subjects to replicate 3 criterion positions was examined on subjects' right shoulders by using an isokinetic dynamometer. Three criterion positions were the 50th, 75th, and 90th percentiles of each individual's total passive shoulder rotation range measured from the full internal rotation position. Main Outcome Measure: Repositioning accuracy, indicating the difference in degrees between the criterion and matching positions. Results: All subjects were able to reproduce the criterion position near the end of external rotation range more accurately and consistently than in the middle range of motion (ROM). Conclusions: Position sense acuity at the shoulder complex varied across the ROM and may be enhanced near the end of rotation range where there is more tension on the restraints to movement. Therefore, an individual's ROM should be factored into any attempt to assess or rehabilitate shoulder proprioception.