External rotator strength deficits in non-athletic people with rotator cuff related shoulder pain are not associated with pain intensity or disability levels

Abstract

BackgroundStrength deficits are often reported in people with rotator cuff related shoulder pain. However, these have mainly been tested in athletic populations and pain interference with testing has not been considered. ObjectivesTo examine strength without pain interference in non-athletic people with rotator cuff related shoulder pain and its association with pain intensity and disability. DesignCross-sectional study. MethodsSixty-seven participants with rotator cuff related shoulder pain were assessed for isometric strength of shoulder external rotator and internal rotator muscles without pain interference with a hand-held dynamometer. Strength was normalized (%body weight). Differences in external and internal rotation strength and external:internal rotator strength ratio between symptomatic and asymptomatic sides were examined (Independent t-tests, Wilcoxon rank sum tests). Spearman's rank correlation coefficients were used to examine associations between strength and pain and disability levels. ResultsThere was no significant difference in internal rotator strength normalized to body weight between symptomatic and asymptomatic sides. There was a significant difference in external rotator strength normalized to body weight (p < .001) and external:internal ratio (p < .001) between sides. No significant correlations were found between strength and pain or disability levels. ConclusionNon-athletic people with rotator cuff related shoulder pain had external rotator strength deficits without pain interference during strength testing, which were not associated with pain and disability levels.