Reliability of B‐Mode Sonography of the Abdominal Muscles in Healthy Adolescents in Different Body Positions

OBJECTIVES: The primary aim of this study was to determine the reliability of abdominal sonographic measurements in adolescents. The secondary aim was to determine whether age, sex, or body position had an impact on the reliability of abdominal muscle sonographic measurements in adolescents. METHODS: Sixty-nine asymptomatic participants aged 10 to 15 years without any postural faults participated in the study. The participants were divided into 3 age groups: 10 to 11, 12 to 13, and 14 to 15 years, according to their sex. All participants underwent 3 measurements of the thickness of the transversus abdominis, internal oblique, and external oblique muscles on both sides of the body in the supine, sitting, and standing positions. The participants' measurements were taken at the end of normal exhalation, and the values were recorded in millimeters. RESULTS: Regardless of the participant's age, sex, and body position, the results for the 3 measurements (intraclass correlation coefficient [ICC(3,3)]) for the transversus abdominis and internal oblique ranged from 0.81 to 0.99. With reference to the external oblique, intraexaminer reliability (ICC(3,3)) in the supine position ranged from 0.81 to 0.98, whereas in the sitting and standing positions, it fluctuated from 0.63 to 0.96. CONCLUSIONS: Sonography for assessment of the internal oblique and transversus abdominis muscles in different body positions in healthy adolescents aged 10 to 15 years was found to have reliability. To obtain high measurement reliability for the transversus abdominis and internal oblique at rest, at least 2 measurements should be performed, regardless of age, sex, or resting body position. Performing 3 measurements of the external oblique guarantees satisfactory reliability only in the supine position.