Objective: The purpose of this study was to establish a reliable method for measuring transversus abdominis thickness in asymptomatic human subjects in supine lying, standing and walking.
Design and methods: This was a single operator reliability study using ultrasound imaging to measure 22 subjects on three separate occasions. A purpose built high-density foam reinforced belt was used to house and position the transducer over the mid-point of the transversus abdominis. Each subject was imaged in supine, standing, and treadmill walking at 3 kph. Intraclass correlation coefficients and standard error of measurement analysis were used to measure the data.
Results: The correlation coefficient data analysis resulted in intraclass correlation coefficients of 0.94 (standard error of measurement 0.35) in supine lying, 0.88 (0.66) in standing and 0.88 (0.56) in walking.
Conclusion: The method described is a reliable tool for measuring changes in thickness of transversus abdominis in supine lying, standing and walking.
Relevance: This procedure has the potential to detect dysfunctional changes in abdominal muscle activity for patients with low back pain in a functional setting.