## 4 Discussion  
This study's objectives were comprehensively addressed, presenting the following key findings: The individuals with SIS exhibited significantly lower shoulder muscle strength and JPS in various directions compared to healthy controls. Additionally, strong positive correlations were identified between shoulder muscle strength and JPS among the SIS individuals, emphasizing the interplay between these factors. Furthermore, pain was found to partially mediate the relationship between muscle strength and JPS in SIS, highlighting the crucial role of pain management in SIS rehabilitation. These results enhance our understanding of the intricate dynamics among these variables and their clinical implications for managing SIS. In line with previous research [38; 39; 40], the findings of our study provide crucial insights into the profound functional deficits experienced by individuals with SIS when compared to a healthy control group. These deficits are evident in two fundamental aspects of shoulder function, namely, muscle strength and joint position sense, each playing a critical role in shoulder biomechanics and overall upper extremity function [41]. The reduced muscle strength observed among individuals with SIS is multifactorial. It is primarily attributed to the presence of pain and inflammation, which can lead to pain-related inhibition of muscle activation and subsequent disuse atrophy [42; 43]. Additionally, altered neuromuscular control patterns induced by pain can compromise coordinated muscle recruitment during shoulder movements, further contributing to strength deficits [43]. These findings are consistent with those reported in previous studies, highlighting the importance of addressing pain management and performing muscle-strengthening interventions in the rehabilitation of individuals with SIS in order to improve their functional capacity and quality of life [42; 43]. The compromised proprioceptive ability of SIS individuals can be attributed to several factors, including pain-induced alterations in sensory feedback mechanisms and structural changes within the shoulder joint that mechanically interfere with proprioceptive receptors [44]. These proprioceptive deficits can negatively impact motor control and joint stability, potentially contributing to recurrent episodes of shoulder impingement and pain [33; 45; 46]. The observed reductions in muscle strength and proprioception among individuals with SIS find substantial support in the existing body of research within the realm of shoulder pathology and rehabilitation [47; 48; 49]. These studies, including those reported by [PERSON] and [PERSON] [50], [PERSON] et al. [51], [PERSON] et al. [52], and [PERSON] et al. [53], collectively corroborate our findings. They emphasize the prevalence of biomechanical alterations, muscle weaknesses, scapular dysfunctions, altered shoulder kinematics, and muscle imbalances and the clinical relevance of addressing muscle strength and proprioception for individuals with impingement-related symptoms [54; 55]. The substantial effect sizes and highly significant \(p\)-values in our study further underscore the functional deficits associated with SIS. These insights emphasize the imperative for comprehensive rehabilitation approaches intended to ameliorate both muscle weakness and proprioceptive impairments in SIS patients, ultimately enhancing their overall shoulder function and quality of life. Our findings illuminate intriguing connections between muscle strength and proprioception in various shoulder directions. Notably, we observed a strong positive correlation between shoulder flexor strength and JPS during flexion (r = 0.62, \(p<\) 0.001), indicating that individuals with greater flexor strength tend to have more accurate proprioceptive perception during flexion movements. This finding underscores the interplay between muscle strength and proprioception, suggesting that improved muscle strength may contribute to enhanced proprioceptive acuity [56; 57].