Shoulder Muscles Strength, Rotators Strength Ratios, And Range of Motion in Relation to Pain, and Disability in Patients with Subacromial Impingement Syndrome: A Correlation Study

Abstract

Objective: This research examined the relationship between shoulder strength, external/internal rotators (EX/IR) ratio, and shoulder mobility, with pain and function disability in subjects with sub-acromial impingement syndrome (SIS).

Design: Cross-sectional study

Methods: Sixty subjects with SIS aged 30 to 40 years. Shoulder pain level was assessed by the visual analog scale (VAS). Shoulder functional impairment was assessed by the Disability of Arm, Shoulder and Hand index (DASH). The active ranges of motion (ROM), of shoulder flexion, abduction, external, and internal rotations, were measured using an inclinometer. Shoulder isometric muscles strength (IMS) including internal (IR) and external rotators (ER), flexors, and abductors, were assessed by the hand-held dynamometer (HHD). The ER/IR strength ratio was calculated from recorded IMS in the previous step.

Results: A statistically significant negative moderate correlation was identified between shoulder function impairment and shoulder flexors, abductors, and external rotators IMS, and flexion ROM. A statistically significant negative moderate correlation was found between pain intensity and external rotators IMS, flexion and abduction ROM (p< 0.05). There is no correlation between shoulder function impairment or pain, relevant to internal rotators IMS, ER/IR ratio, and internal rotation ROM (p > 0.05).

Conclusion: The findings of current research indicate a negative correlation between muscle strength, and shoulder mobility with pain intensity and function disability, but the ER/IR ratio is not correlated with pain and disability.

Key words: Shoulder impingement; pain; shoulder function disability; mobility and muscle strength.