['To examine activation patterns of the myofascial chain in women experiencing chronic low back pain (CLBP) and women without CLBP during a prone hip extension (PHE) test.', 'Cross-sectional.', 'Clinical research laboratory.', 'Fifteen women experiencing CLBP and 15 women without CLBP.', 'Surface electromyographic recordings from the posterior oblique sling during PHE.', 'Two-sample t-tests were used to compare demographic information and electromyographic signal amplitude of the posterior oblique sling between groups.', 'Women with CLBP exhibited significantly increased normalized electromyographic signal amplitudes in the contralateral latissimus dorsi (P\xa0= .01), contralateral elector spinae (P\xa0< .01), ipsilateral elector spinae (P\xa0< .01), ipsilateral gluteus maximus (P\xa0= .03), and ipsilateral biceps femoris (P\xa0= .02) compared with women without CLBP.'] Do patients with low back pain demonstrate increased activity of the posterior oblique sling muscle during prone hip extension?