Objective: The purpose of this study was to compare the shoulder rotator strength (SRS) and handgrip strength (HS) in affected side with that in unaffected side in patients with unilateral subacromial impingement syndrome (SIS), and to evaluate the relationship of SRS with duration of symptoms, handgrip strength, pain, disability, quality of life (QOL), and emotional status.

Materials and Methods: Forty-five patients with unilateral SIS were included. SRS and HS were assessed bilaterally (affected and unaffected side) by isokinetic dynamometer and handheld dynamometer, respectively. Shoulder pain was evaluated by the Visual Analogue Scale, disability with the Shoulder Pain and Disability Index, emotional status by the Beck Depression Inventory, and QOL was assessed by the Short Form-36 in all patients.

Results: SRS and HS values of the affected side were significantly lower than the unaffected side (p<0.05). On the affected side, SRS was positively correlated with HS and negatively correlated with depression (p<0.05). QOL parameters were positively correlated with peak torque value of affected shoulder external rotators at 180°/sec (p<0.05). However, there was no relationship of SRS with duration of symptoms, pain, and disability levels (p>0.05).

Conclusion: The results of this study showed that SRS and HS deficits could be detected in patients with SIS. In these patients, duration of symptoms, pain intensity and level of disability may not have any impact on SRS. Decreased SRS may adversely affect HS, emotional status, and QOL.