Shoulder position sense during passive matching and active positioning tasks in individuals with anterior shoulder instability.
BACKGROUND
Altered neuromuscular control due to compromised joint position sense may contribute to recurrent shoulder instability.


OBJECTIVE
The purpose of the present study was to examine whether individuals with anterior shoulder instability exhibit larger shoulder position sense errors than those with healthy shoulders in both passive matching and active positioning.


METHODS
This was a between-groups study with repeated measures.


METHODS
Ten people with anterior shoulder instability and 15 people with healthy shoulders participated in the study. Shoulder position sense was examined with 3 different protocols (passive motion to remembered shoulder rotation angles and active shoulder abduction and rotation to verbally specified positions) in positions of both mid-range and end-range of motion.


RESULTS
Participants with unstable shoulders exhibited significantly larger errors (by 1.8° on average) in perception of shoulder position compared with those with healthy shoulders during passive matching. During active positioning, participants with unstable shoulders were able to voluntarily move the shoulder to verbally specified angles as accurately as those with healthy shoulders in both abduction (0.85° difference) and rotation (0.99° difference) tasks.


CONCLUSIONS
Results of this study indicate that people with unstable shoulders can perceive shoulder angles as accurately as people with healthy shoulders in activities with voluntary arm movements. Compared with passive matching, better information from muscle spindles and other sources during voluntary arm movements may compensate for the potential joint position sense deficits after the injury. Therefore, individuals with an unstable shoulder may have adequate neuromuscular control to engage proper protective mechanisms to stabilize the shoulder joint during functional activities.
Department of Nursing and Rehabilitation Sciences, Angelo State University, ASU Station 10923, San Angelo, TX 76909-0923, USA. you-jou.hung@angelo.edu
You-jou
YJ
Hung
Warren G
WG
Darling
D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology* / Q000534:rehabilitation*; D008297:Male; D011434:Proprioception / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000503:physiopathology*