Shoulder mobility restriction is a central feature in individuals with frozen shoulders, a musculoskeletal condition that significantly impacts the functionality of those affected. Psychological factors such as anxiety, depression, kinesiophobia, and pain catastrophizing, along with sleep quality, have been associated with pain and disability in various chronic pain conditions. However, it remains unclear which of these factors are most strongly associated with shoulder mobility deficits in individuals with frozen shoulder.

To analyze the association of pain, disability, psychological factors (anxiety, depression, kinesiophobia, pain catastrophizing) and sleep quality with shoulder mobility deficits in individuals with frozen shoulder.

A cross-sectional study conducted via video call using Google Meet®. Shoulder mobility was assessed using Kinovea® software, considering flexion, abduction (in degrees), and external rotation (in centimeters) for the painful and non-painful sides. Pain and disability were measured using the Shoulder Pain and Disability Index (SPADI), while self-efficacy was evaluated using the Pain Self-Efficacy Scale (PSEQ-10). Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS), kinesiophobia with the Tampa Scale for Kinesiophobia-11 (TSK-11), pain catastrophizing with the Pain Catastrophizing Scale (PCS), and sleep quality using the Pittsburgh Sleep Quality Index (PSQI). Data analysis was performed using multiple linear regression with two distinct models. In the first model, the external rotation mobility deficit (difference between painful and non-painful sides) was the dependent variable. In the second, the arm elevation deficit was calculated as the average of the differences in flexion and abduction, and was also a dependent variable. The other variables were considered independent.

Ninety-six individuals participated, with 57 diagnosed with primary frozen shoulder and 39 with secondary frozen shoulder [72 women, mean age = 53.1 ± 10.8 years, BMI = 26.3 ± 4.8 kg/m²]. For external rotation, none of the variables were associated with mobility deficits. However, for arm elevation, pain was significantly associated, contributing 5.5% to the variation in mobility (f(1,94) = 6.52, p < 0.012, adjusted R² = 0.055, RMSE = 19.35). Other psychological factors and sleep quality were not significantly associated with shoulder mobility deficits.

Pain was significantly associated with shoulder mobility restriction, particularly in arm elevation, although with a modest contribution. Psychological factors and sleep quality did not demonstrate a relevant association with mobility deficits.

These findings suggest that while pain has some impact on shoulder mobility, other factors not investigated in this study may have a more significant influence on mobility restriction. Psychological factors and sleep quality should likely not be the primary focus in addressing mobility deficits but could be incorporated as complementary strategies aimed at the patient&apos;s overall well-being.