Abstract
[Purpose] To study the activities of the deep abdominal muscles during trunk rotation using ultrasound imaging. [Subjects] The subjects were 10 healthy persons with no lower limb or trunk disorders, and 6 chronic low back pain (LBP) patients. [Methods] In the sitting position, trunk rotation was performed voluntarily, and passively with a device. The thickness changes in the transversus abdominis (TrA) during performance of the task were compared between the healthy subjects and LBP patients. [Results] We found that the TrA thickness increased unilaterally in trunk rotational movement of the healthy subjects, but not in the LBP patients. [Conclusion] The difference observed in the TrA activities of healthy subjects and LBP patients suggests TrA contributes to trunk rotation, and TrA functionality is one aspect of the difference between healthy subjects and LBP patients.
