Investigating the relationship between proprioception and muscle strength in individuals with shoulder impingement syndrome

Objective: The aim of this study was to examine the relationship between proprioceptive sense and muscle strength in individuals with shoulder impingement syndrome. Materials and Methods: The study included 45 participants (15 males and 30 females, aged 22-74) with shoulder impingement syndrome and pain for at least 1 month. The study assessed shoulder proprioception on both the painful and non-painful sides using the Goniometer Pro application and shoulder muscle strength with the K-Force hand dynamometer. Comparisons of proprioception and muscle strength between both sides were made using the paired sample t-test for parametric data and the Wilcoxon rank-sum test for non-parametric data. The relationship between proprioception and muscle strength was analyzed using Pearson's correlation for parametric data and Spearman's rank correlation for non-parametric data. Results were considered significant at 0.05 level. Results: A significant difference was found between the proprioception and muscle strength of the painful and non-painful shoulders; the painful side exhibited lower proprioception and muscle strength. Significant correlations were observed between proprioception and muscle strength of both the painful and non-painful sides. These correlations were stronger on the painless side across various parameters. Proprioception during 15° and 30° internal rotation and 15° external rotation were more closely related to muscle strength on the non-painful side. Meanwhile, proprioception during 30° flexion and 30° abduction were more closely associated with muscle strength on the painful side. Conclusions: Shoulder impingement syndrome can impact the proprioception and muscle strength, leading to a decline in function. In the case of shoulder impingement, proprioception is more related to shoulder flexion and abduction muscle strength. We recommend incorporating exercises that enhance proprioception, particularly those that strengthen flexion and abduction muscles, in the rehabilitation of shoulder impingement syndrome.