Altered muscular activation during prone hip extension in women with and without low back pain

Background: Altered movement pattern has been associated with the development of low back pain (LBP). The purpose of this study was to investigate the activity pattern of the ipsilateral erector spinae (IES) and contralateral erectorspinae (CES), gluteus maximus (GM) and hamstring (HAM) muscles during prone hip extension (PHE) test in women with and without LBP. A cross-sectional non-experimental design was used. Methods: Convenience sample of 20 female participated in the study. Subjects were categorized into two groups: With LBP (n = 10) and without LBP (n = 10). The electromyography (EMG) signal amplitude of the tested muscles during PHE (normalized to maximum voluntary electrical activity (MVE)) was measured in the dominant lower extremity in all subjects. Results: Statistical analysis revealed greater normalized EMG signal amplitude in women with LBP compared to non-LBP women. There was significant difference in EMG activity of the IES (P = 0.03) and CES (P = 0.03) between two groups. However, no significant difference was found in EMG signals of the GM (P = 0.11) and HAM (P = 0.14) among two groups. Conclusion: The findings of this study demonstrated altered activation pattern of the lumbo-pelvic muscles during PHE in the women with chronic LBP. This information is important for investigators using PHE as either an evaluation tool or a rehabilitation exercise. © 2011 Arab et al.