[Altered hip muscle activation in patients with chronic non-specific low back pain].

Background: The aim of this study was to examine postural control in patients with chronic non-specific low back pain (CNRS). Furthermore the influence of visual information (eyes open versus eyes closed) was analyzed.

Material And Methods: A total of 8 patients with CNRS and 12 healthy control subjects were examined. Surface electromyography (SEMG) recordings were made from 5 trunk and 5 lower limb muscles as well as one hip muscle during application of distal lateral perturbation.

Results: Healthy controls (mean ± standard deviation: 96.42±64.77 µV) showed a significantly higher maximum amplitude of the gluteus medius muscle in comparison to patients with CNRS (56.29±39.63 µV). Furthermore activation of several lower limb muscles was found to be dependent on visual information.

Conclusion: Patients showed an altered reflex response of the gluteus medius muscle which could be associated with reduced hip stability.