Quadriceps Femoris Versus Lumbar Paraspinal Soft Tissue Mobilization in Patients with Low Back Pain Associated with Lumbar Disc Herniation: A Randomized Controlled Trial

Backgroundand Objectives: Soft tissue mobilization is commonly used to manage low back pain (LBP), but it remains unclear whether treatment outcomes differ according to the anatomical region targeted. To compare the effects of soft tissue mobilization applied to the quadriceps femoris and lumbar paraspinal muscles on pain intensity, anterior pelvic tilt, lumbar flexion excursion, and disability in patients with lumbar disc herniation (LDH) presenting with chronic LBP and quadriceps femoris shortening. Materials and Methods: Parallel-group randomized controlled trial. Forty participants were randomly assigned to either quadriceps femoris or lumbar paraspinal soft tissue mobilization (n = 20 per group). Both groups received soft tissue mobilization twice weekly for 4 weeks. Pain intensity, anterior pelvic tilt, lumbar flexion excursion, and disability were assessed at baseline and post-intervention. The primary analysis followed the intention-to-treat principle using linear mixed models with all available observations. Results: Pain intensity and disability decreased in both groups, without significant between-group differences in change. For pain intensity, the estimated between-group difference was −0.39 points (95% CI, −0.91 to 0.13; p = 0.143), and for disability, it was −2.76 percentage points (95% CI, −7.55 to 2.04; p = 0.260). Significant group × time interactions were observed for anterior pelvic tilt (between-group difference, −2.79°; 95% CI, −3.24 to −2.34) and lumbar flexion excursion (between-group difference, 1.01 cm; 95% CI, 0.83 to 1.19), favoring the quadriceps femoris group (both p < 0.001). Conclusions: Pain intensity and disability improved over time following both soft tissue mobilization protocols, without significant between-group differences. Quadriceps femoris mobilization produced greater short-term improvements in anterior pelvic tilt and lumbar flexion excursion than lumbar paraspinal mobilization. These findings suggest that quadriceps femoris mobilization may provide additional benefits for movement-related outcomes in patients with LDH presenting with LBP and quadriceps femoris shortening.