Association of Pain Intensity with Clinical Examination Parameters in Patients with Low Back Pain: A Cross-sectional Study

Abstract Background: Low back pain (LBP) is a leading cause of global disability, often requiring a multidimensional clinical assessment. Although pain intensity is typically measured using the Numerical Rating Scale (NRS), its relationship with objective clinical parameters remains unclear. Objective: The objective of this study was to examine the association between self-reported pain intensity and clinical examination findings – specifically spinal range of motion (ROM), finger-to-floor distance (FFD) and localised tenderness – in patients with persistent LBP. Methodology: This cross-sectional study was conducted at a tertiary care physical medicine and rehabilitation department, including 384 patients aged 18 years and above with LBP lasting more than 1 week. Pain intensity was recorded using the NRS. Clinical measures included spinal ROM (flexion, extension and lateral bending), FFD and lumbosacral tenderness graded on a 5-point scale. Correlations were assessed using Spearman’s rank test, and predictors were identified through multiple linear regression analysis. Results: The mean age was 49.47 years, and NRS Score showed strong positive correlations with tenderness grade (ρ = 0.870, P < 0.001) and FFD (ρ = 0.873, P < 0.001) and a moderate negative correlation with spinal flexion ROM (ρ = –0.483, P < 0.001). No significant associations were found with age, body mass index, symptom duration or spinal extension/lateral bending. Regression analysis revealed that tenderness, FFD and spinal flexion were significant predictors of pain intensity, explaining 88.5% of the variance in NRS scores ( R ² = 0.885). No gender differences were observed. Conclusion: Pain intensity in LBP is significantly associated with localised tenderness and reduced spinal flexibility. In contrast, demographic variables and certain biomechanical parameters showed no meaningful correlation, underscoring the value of functional and tactile assessments in clinical evaluation.