The influence of kinesiophobia on trunk muscle voluntary responses with pre-programmed reactions during perturbation in patients with chronic low back pain

The purpose of this study was to examine the relation between fear of movement and perturbation induced electromyographic global trunk muscle voluntary responses with pre-programmed reactions among persons with chronic low back pain (CLBP). CLBP subjects (n = 25) were challenged to unexpected and expected perturbations on stable and unstable surfaces. 'Tampa scale for kinesiophobia - Adjusted version-13' was used to measure kinesiophobia. Regression analysis revealed significant negative correlation between kinesiophobia scores and voluntary responses of rectus abdominis (RA) for unexpected perturbations on stable (r = -0.69, 95% of CI: -0.85 to -0.40, p < 0.000, r ² = 0.41) and unstable surfaces (r = -0.47, 95% of CI: -0.72 to -0.09, p < 0.018, r ² = 0.29). The activity of erector spinae was not influenced by most of testing conditions in the study except task on unstable surface for expected perturbation (r = -0.593, 95% of CI: -0.8 to -0.25, p = 0.002, r ² = 0.15). RA activity and kinesiophobia score of the CLBP population was significantly inversely associated during anteriorly directed unexpected perturbations. In our study, the significant association between fear of movement and the trunk muscle responses was differentially influenced by expected and unexpected postural demands.