Profile and association between pain sensitivity and physical fitness in individuals with chronic low back pain.

This study examined the profile and associations between pain sensitivity, psychological factors, and physical fitness in adults with chronic low back pain (LBP), and explored whether these associations differed from healthy controls.MethodsThirty‑six adults (18 chronic LBP; 18 healthy controls) completed questionnaires assessing psychological profiles (Pain Catastrophizing Scale; Hospital Anxiety and Depression Scale), disability (Oswestry Disability Index), and pain sensitization (Central Sensitization Inventory). Quantitative sensory testing (pressure pain threshold, vibration detection threshold, mechanical temporal summation) was performed at local (low back) and distal sites. Physical fitness was assessed using the 6‑Minute Walk Test, Back Extension Endurance Test, and Modified Bruce Treadmill Test. Between‑group comparisons analysed using t‑tests or Wilcoxon tests, while associations between pain sensitivity, psychological factors, and physical fitness were examined using multiple linear regression.ResultsCompared with healthy controls, individuals with chronic LBP mild pain and functional disability demonstrated significantly higher anxiety and depression (t = - 2.376, p = 0.023), disability (t = - 4.276, p < 0.001), catastrophizing (Z = - 2.146, p = 0.032), and Central Sensitization Inventory scores (t = 0.982, p = 0.035), alongside lower vibration detection thresholds at the low back (Z = - 3.338, p < 0.001) and shorter 6‑Minute Walk distance (t = 2.124, p = 0.041). Regression modelling showed that sensory, psychological, and anthropometric variables explained 60% of the variance in walking distance (adjusted R² = 0.60, p = 0.002). Greater distal PPT and height predicted longer distance, whereas greater temporal summation (local and distal), higher weight, and higher psychological distress predicted shorter distance. No sensory or psychological variables independently predicted back extensor endurance or estimated aerobic capacity. Exploratory subgroup analyses revealed that walking performance in healthy controls was primarily anthropometric‑driven, whereas in chronic LBP, nociplastic sensory features and psychological distress showed stronger associations.ConclusionsIndividuals with chronic LBP demonstrated altered somatosensory and psychological profiles and reduced walking capacity. Walking performance was most strongly associated with pain sensitivity and psychological distress, particularly among those with chronic mild LBP. Future studies involving individuals with higher pain intensity and chronicity are warranted to clarify mechanistic pathways and potential mediation effects.