Tehran University of Medical Sciences Journal of Modern Rehabilitation 2538-385X 16 3 2022 07 01 244 251 Hassan Tamartash Department of Physiotherapy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Farid Bahrpeyma Department of Physiotherapy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. Manijhe Mokhtari Dizaji Department of Medical Physics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran. 2021 03 07 2021 07 12 Introduction: This study aims to evaluate the effect of lumbar myofascial release (MFR) technique on pain and thickness of the lumbar fascia tissue in patients with non-specific low back pain. Materials and Methods: In this clinical trial, 20 subjects with non-specific low back pain were treated by MFR on the lumbar region at 4 sessions. Low back pain severity and thickness of the lumbar fascia tissue were assessed by ultrasonographic imaging before and after the intervention. Results: Subjects showed significant reduction in lumbar fascia thickness (P=0.000) and low back pain severity (P=0.000). Conclusion: The lumbar MFR technique is effective in patients with non-specific low back pain due to reducing the lumbar fascia thickness and low back pain. https://jmr.tums.ac.ir/index.php/jmr/article/view/398