Associations of pain intensity and pressure pain threshold with neck disability in individuals with upper trapezius myofascial trigger points: a cross-sectional study

Active myofascial trigger points (MTrPs) in the upper trapezius are associated with pain, mechanical pain sensitivity, and functional limitations. However, the independent associations of pressure pain threshold (PPT) and pain intensity with neck-related disability remain insufficiently characterized. To examine the univariable and independent associations of PPT and numeric pain rating scale (NPRS) scores with neck disability index (NDI) scores in individuals with active upper trapezius MTrPs. This cross-sectional study included 90 men aged 25–38 years with unilateral active upper trapezius MTrP-related neck or shoulder pain. PPT was measured using a pressure algometer and expressed in kgf/cm 2 . Pain intensity and neck-related disability were assessed using the NPRS (0–10 points) and NDI (0–50 points), respectively. Pearson correlations and univariable ordinary least squares regression models were used to examine bivariate associations. A simultaneous multiple linear regression model included age, PPT, and NPRS as explanatory variables for NDI. Two-sided statistical significance was set at p < 0.05. PPT was strongly and inversely correlated with NPRS ( r = −0.826, 95% confidence interval [CI] −0.882 to −0.747; p < 0.001) and NDI ( r = −0.810, 95% CI −0.871 to −0.724; p < 0.001). NPRS was strongly and positively correlated with NDI ( r = 0.834, 95% CI 0.757–0.888; p < 0.001). In univariable models, PPT and NPRS explained 65.6% and 69.5% of the observed NDI variance, respectively. The simultaneous model was statistically significant, F (3,86) = 82.835, p < 0.001, and explained 74.3% of the observed NDI variance (adjusted R 2 = 0.734). After mutual adjustment, lower PPT ( B = −2.311, standardized β = −0.379, 95% CI −3.487 to −1.135; p < 0.001) and higher NPRS scores ( B = 1.317, standardized β = 0.509, 95% CI 0.814–1.821; p < 0.001) remained independently associated with greater NDI scores. Age was not independently associated with NDI ( B = 0.049, standardized β = 0.044, 95% CI −0.077 to 0.175; p = 0.441). Lower PPT and higher pain intensity were independently associated with greater neck-related disability in men with active upper trapezius MTrPs. The model, including age, PPT, and NPRS, explained a substantial proportion of the observed variation in NDI. However, these cross-sectional findings represent concurrent associations and should not be interpreted as evidence of causality or validated prognostic performance. Further investigation is needed to assess generalizability to women, other age groups, and broader neck-pain populations.