Effects of Different Verbal Instructions in Healthy Adults and Patients With Low Back Pain

Segmental stabilization exercise has been shown to be effective in the rehabilitation of low back pain (LBP). Due to the isometric nature of segmental stabilization exercise, manual therapists use various verbal instructions to elicit lumbar multifidus muscle contraction. The purpose of this study was to assess whether or not three verbal instructions would alter muscle thickness of the lumbar multifidus differently in asymptomatic individuals and patients with LBP. Three verbal instructions were selected for this study: (1) swell the muscle underneath the transducer, (2) draw your belly button in towards your spinal column, and (3) think about tilting your pelvis but without really doing it. Lumbar multifidus muscle thickness was determined using parasagittal ultrasound imaging. Measurements of muscle thickness were collected at rest and during verbal instructions from 21 asymptomatic adults and 21 patients with LBP. Percent changes of muscle thickness during contraction and at rest were compared between groups and across verbal instructions.