Publications

Purpose: Chronic neck pain (CNP), which ranks as the fourth leading cause of disability worldwide, negatively affects quality of life and impairs activities of daily living. This study aimed to examine the relationships between muscle biomechanical properties, pain, disability, and demographic factors in individuals with CNP.

Design: Cross-sectional study.

Methods: Forty-one participants (mean age 29.63 ± 12.46 years; 78% female) were included. Muscle properties of the trapezius and sternocleidomastoid (SCM) were assessed using myotonometry, while pain intensity (NRS), multidimensional pain impact (PEG), and disability (Neck Disability Index [NDI], Bournemouth Neck Pain Questionnaire [BNPQ]) were recorded.

Results: Significant positive correlations were found between age and trapezius/SCM tone, stiffness, and decrement values (r = 0.312–.811, p < .05 to <.001), ranging from weak to very strong. Additionally, SCM decrement showed a moderate correlation with BMI (r = 0.439, p = .004). Pain measures demonstrated strong associations with disability: NRS correlated with NDI (r = 0.448, p = .003) and BNPQ (r = 0.481, p = .001), while PEG showed stronger correlations with NDI (r = 0.637, p < .001) and BNPQ (r = 0.615, p < .001). Regression analyses showed that pain measures were significantly associated with disability, with PEG explaining a greater proportion variance (NDI R²=.406, BNPQ R²=.378) compared to NRS (NDI R²=.219, BNPQ R²=.213). No direct associations were found between muscle biomechanical properties and pain.

Conclusions and Clinical Implications: These findings indicate that muscle biomechanical properties are associated with demographic factors such as age and BMI, whereas pain—particularly when assessed using multidimensional instruments—is more strongly associated with disability in individuals with CNP.

Keywords: neck pain, muscle tonus, stiffness, disability

In conclusion, this study highlights significant age-related changes in the biomechanical properties of the trapezius and SCM muscles and demonstrates a strong relationship between pain intensity and disability in individuals with CNP. These findings address an important knowledge gap by showing that, despite measurable changes in muscle properties with aging, such alterations alone may not explain pain severity or disability in individuals with chronic neck pain. The observed relationship between pain and disability underscores their clinical relevance and emphasizes the importance of addressing functional impact alongside symptom intensity in clinical practice. The lack of association between muscle biomechanical parameters and clinical outcomes suggests that central sensitization, psychosocial factors, or movement-related behaviors may play a more prominent role in pain-related disability than previously assumed. Clinically, these results indicate that assessment and treatment strategies focusing solely on local muscle properties may have limited effectiveness, and a more multidimensional approach may be warranted. Future research should employ longitudinal designs, include broader and more heterogeneous populations, and explore potential mediating mechanisms to better inform targeted and clinically meaningful interventions for chronic neck pain.