Reliability of Ultrasound Imaging of the Transversus Deep Abdominial, Internal Oblique and External Oblique Muscles of Patients with Low Back Pain Performing the Drawing-in Maneuver

[Purpose] The purpose of this study was to investigate the reliability of ultrasound imaging (USI) measurements of muscle thicknesses of patients with low back pain (LBP) performing the abdominal drawing-in maneuver (ADIM) [Subjects] Twenty patients with LBP were the subjects. [Methods] Muscle thickness measurements of transversus abdominis (Tra), internal obliques (IO), and external obliques (EO) muscles were measured using ultrasound imaging at rest and during performance of the ADIM. [Results] The intra-examiner reliability estimates ranged from 0.55 to 0.97 in the rest position, and from 0.82 to 0.95 during ADIM. The inter-examiner reliability estimates ranged from 0.77 to 0.98 in the rest position, and from 0.86 to 0.98 during ADIM. [Conclusion] ADIM thickness measurements of the TrA, IO, and EO muscles in patients with LBP based on the mean of 2 measures are highly reliable when taken by a single examiner and adequately reliable when taken by different examiners.