Psychometric Properties of the Deep Muscle Contraction Scale for Assessment of the Drawing-in Maneuver in Patients With Chronic Nonspecific Low Back Pain

Study Design A prospective cohort study. Background Motor control dysfunctions have been commonly reported in patients with chronic nonspecific low back pain (LBP). Physical therapists need clinical tools with adequate psychometric properties to assess such patients in clinical practice. The deep muscle contraction (DMC) scale is a clinical rating scale for assessing patients' ability to voluntarily contract deep abdominal muscles. Objectives To investigate the intrarater reliability, floor and ceiling effects, internal and external responsiveness, and correlation analysis (with ultrasound measures) of the DMC scale in patients with chronic nonspecific LBP undergoing a lumbar stabilization exercise program. Methods Sixty-two patients with chronic nonspecific LBP were included. At baseline, self-report questionnaires were administered to patients and a trained assessor evaluated abdominal muscle recruitment with the DMC scale and ultrasound imaging. Four ratios of the change in abdominal muscle thickness b...