Is there a relationship between psychological status and posture in chronic low back pain?

Abstract Context Chronic non-specific low back pain (CNLBP) is a major public health. Numerous studies have evaluated the contribution of posturology in the assessment and the rehabilitation of this pathology. The aim of our work was to investigate the relationship between posturological and muscular assessments in patients with CNLBP. Methods It’s about an observational, descriptive, and cross-sectional study. The muscle assessment included Quadriceps Femoris flexibility using the heel-to-buttock distance and Hamstrings flexibility using the popliteal angle. Isometric muscle strength of the extensor and flexor muscles of the trunk was assessed by the Biering-Sorensen test and the Shirado test, respectively. The evaluation of static postural control was performed by the SATEL® force platform in two conditions (opened eyes/closed mouth) and (closed eyes/closed mouth). The chi-square test or Fisher's exact test was used to assess differences between categorical variables, and means were compared using Pearson's or Spearman's correlation tests depending on the distribution of the variables. Comparison between qualitative and quantitative variables was done by ANOVA test for normally distributed variables and Mann-Whitney or Kruskall-Wallis tests for non-normally distributed data. Results Forty patients were included. The study of muscle flexibility according to force plateform parameters showed that left Hamstring stiffness was significantly correlated with XY (p = .037) and with instability in the sagittal plane (p = .036). On the other hand, the stiffness of the anterior rectus muscles (right and/or left) was significantly correlated with XY (p = 0.019 for the right muscle and 0.011 for the left muscle) and with postural instability in the frontal plane (p = .015 for the right muscle and .026 for the left muscle). We also founded a significant association between the increase in Romberg quotient and right Hamstring stiffness (p = .003). Conclusions Our study as well as literature findings suggest that the Quadriceps Femoris and the Hamstrings play have a significant role in core stability of patients with chronic non-specific back pain. A larger number of patients and a control group would have made it possible to establish a cause- effect relationship between Quadriceps Femoris, Hamstrings and static postural control abnormalities.