Instrument-assisted release of quadratus lumborum on pelvic posture and iliopsoas muscle length in non-specific low back pain: a double blinded placebo controlled trial

Objective The iliopsoas and quadratus lumborum muscles, linked anatomically, stiffen and contribute to anterior pelvic tilt in non-specific low back pain (NSLBP). Though iliopsoas’ deep location limits direct release, instrument-assisted soft tissue mobilisation (IASTM) is gaining popularity, requiring further investigation. The primary objective was to evaluate IASTM effects on iliopsoas length, pelvic posture, pain and disability in NSLBP participants. Methods Thirty-two participants with NSLBP and quadratus lumborum tightness were randomly allocated using a simple random method in the present double-blinded (assessor and patients) placebo-controlled trial. In addition to conventional physiotherapy (Interferential and Ultrasound therapies) the experimental group (n = 16) received IASTM, while the control group (n = 16) received sham IASTM on alternate days for 5 sessions across 10 days, each session lasting for 45 min. The primary outcomes included iliopsoas length (measured by ultrasonography and modified Thomas test), pelvic posture (APCES software) while the secondary outcomes were Quebec back pain disability scale (QBPDS), and pain intensity by visual analogue scale (VAS). Assessments were done pre- and post-treatment (10 days). Results Significant increases in iliopsoas length (effect size right: 0.76, left: 0.81), decreased modified Thomas test angles (effect size right: 0.78, left: 0.80), reduced pelvic tilt (effect size: 1.07), disability score (effect size: 1.44) and VAS (effect size: 1.47) were observed in the IASTM group with p < 0.001. The between-groups analysis showed a significant difference in the IASTM group for all outcomes (p < 0.05) except the disability scale (p > 0.05). Conclusions IASTM of quadratus lumborum significantly reduced pelvic tilt and increased iliopsoas length, suggesting its potential for effective soft tissue release in NSLBP.