Abstract: Objective To investigate the position sense in chronic non-specific low back pain (CNLBP) patients, and the correlation to pain and endurance of psoas muscles. Methods From January, 2014 to May, 2015, 30 patients with CNLBP and other 30 healthy subjects were measured spine flexion and extension position sense absolute error (AE) and psoas endurance with Biodex System 3 synchronously, and the patients were self-assessed the pain in lumbar with Numerical Rating Scale (NRS). The Pearson correlation coefficient of AE to psoas endurance and NRS was calculated. Results AE of flexion and extension was both more in the patients than in the healthy (t>; 1.862, P<; 0.05), and the psoas muscle endurance was less (t=2.307, P<; 0.05). AE of flexion (r=-0.71) and extension (r=-0.47) negatively correlated with the psoas muscle endurance in the patients, and positively correlated with NRS score (r=0.78 for flexion, and r=0.49 for extension). AE mildly negative correlated with the psoas muscle endurance (r=-0.38 for flexion, and r=-0.29 for extension). Conclusion Spine sensation has been impaired in CNLBP patients, and may associate with pain and psoas muscles endurance loss.

Key words: chronic non-specific low back pain, position sense, psoas muscles endurance, pain