Original Research ArticlesActivity of the Quadratus Lumborum and Trunk Muscles Relates to Pelvic Tilt Angle During Pelvic Tilt ExercisesOshikawa, Tomoki MS; Adachi, Gen MS; Akuzawa, Hiroshi PhD; Okubo, Yu PhD; Kaneoka, Koji PhD Author Information From the Graduate School of Sport Sciences, Waseda University, Saitama, Japan (TO, GA); Faculty of Sport Sciences, Waseda University, Saitama, Japan (HA, KK); and Faculty of Health & Medical Care, Saitama Medical University, Saitama, Japan (YO). All correspondence should be addressed to: Koji Kaneoka, PhD, Waseda University School of Sport Sciences, 2-579-15 Mikajima, Tokorozawa, Saitama, 359-1192, Japan. This study was supported by a grant-in-aid for scientific research (C) from the Japan Society for the Promotion of Science. All authors are in training. Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.ajpmr.com). American Journal of Physical Medicine & Rehabilitation: December 2020 - Volume 99 - Issue 12 - p 1109-1115 doi: 10.1097/PHM.0000000000001496 Buy SDC Metrics Abstract Objective Pelvic tilt exercises are used clinically to correct lumbopelvic alignment. The anterior and posterior layers of the quadratus lumborum are important for pelvic motor control in the coronal plane. This study aimed to evaluate whether the anterior and posterior activity is related to the pelvic tilt angle during pelvic tilt exercises. Design The study design was single-occasion repeated measures in a randomized manner. Twelve healthy men performed the four directions of the pelvic tilt exercises (anterior or posterior pelvic tilt and lateral pelvic elevation on the ipsilateral or contralateral measurement side). The electromyographies of the anterior and posterior were recorded using intramuscular fine-wire electrodes and normalized to isometric peak electromyography. Results The activity of the anterior and posterior during lateral pelvic elevation on the ipsilateral measurement side (19.0 ± 16.0 percent of maximal voluntary isometric contraction) was significantly higher than that during other directions of the pelvic tilt exercises (P < 0.01). There was a significant positive correlation between the anterior activity and the maximum change angles of pelvic tilt during lateral pelvic elevation on the ipsilateral measurement side (r = 0.674, P = 0.016). Conclusions The anterior activity was related to a large lateral pelvic elevation angle on the ipsilateral side during pelvic tilt exercises. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.