The Effects of Joint Mobilization and Myofascial Release on Muscle Thickness in Non-Specific Low Back Pain: A Randomized Clinical Trial

<b>Background</b>: Non-specific low back pain is a discomfort that affects individuals at any point in their lives. This study's aim was to determine the effects of myofascial release and joint mobilization on muscle thickness via ultrasonography in individuals experiencing non-specific low back pain. <b>Methods</b>: This double-blinded randomized clinical trial was conducted on 84 participants in three groups: joint mobilization, myofascial release, and a combination of joint mobilization and myofascial release. Data were collected during a two-week treatment regimen (days 1, 4, 8, and 12) and at a one-month follow-up. Ultrasound evaluations were used to measure the thickness of deep lumbar muscles at rest and contraction, i.e., the transverse abdominis (rTrA and cTrA) and lumbar multifidus (rLM and cLM). Repeated-measures ANOVA was utilized to analyze the follow-ups within the groups and among the groups, with post hoc tests conducted to identify specific differences. <b>Results:</b> Significant increases in muscle thickness were observed over time in the transverse abdominis, with improvements in both rTrA (right, <i>p</i> = 0.001; left, <i>p</i> = 0.001) and cTrA (right, <i>p</i> = 0.001; left, <i>p</i> = 0.008). The lumbar multifidus also demonstrated significant changes, with increases in the rLM (right, <i>p</i> = 0.001; left, <i>p</i> = 0.047) and cLM (right, <i>p</i> = 0.004; left, <i>p</i> = 0.037). However, the main effects showed no significant differences in muscle thickness among the groups. <b>Conclusions:</b> Joint mobilization demonstrated increased effectiveness in improving muscle thickness relative to myofascial release and a combination of both treatments for individuals with non-specific low back pain.