The effect of lumbar support on the ultrasound measurements of trunk muscles: a single-blinded randomized controlled trial.

OBJECTIVES To evaluate the effect of lumbopelvic belts on the thickness of lateral abdominal muscles and the cross-sectional area (CSA) of lumbar multifidus (LM) muscles. DESIGN A single-blinded randomized controlled trial. SETTING An academic and tertiary care referral spine and sports medicine center. PARTICIPANTS Sixty healthy volunteers with no history of low back pain in the previous year. METHODS The subjects were allocated into belt and control groups. Lumbar belts were given to the subjects in the belt group, and they were asked to use the belts during the study period except during sleeping hours. The subjects were assessed at baseline and at 4 and 8 weeks. MAIN OUTCOME MEASURES The thickness of lateral abdominal muscles and the CSA of the LM muscles were measured by ultrasound with the patient in the hook-lying position on an examination table. RESULTS The thickness of lateral abdominal muscles and the CSA of LM muscles on both sides decreased significantly among healthy subjects in the belt group after 8 weeks. CONCLUSION The results of this study show that lumbopelvic belts might influence the ultrasonographic measurements of lateral abdominal and LM muscles and thereby spine stability.