Comparison of Abdominal muscle thickness during respiratory phase according to breathing method with and without chronic low back pain: A cross-sectional study

Objective: This study aimed to compare anterior abdominal muscles thickness during different breathing methods between Chronic low back pain (CLBP) and Normal adults (NA). The anterior abdominal wall muscles was measured during the respiratory phase of inspiration and expiration according to breathing methods of general and abdominal breathing. Design: A cross-sectional study Methods: Sixty participants (28 CLBP patients, 29 normal adults) were recruited. Breathing methods were classified into normal breathing (NB) and abdominal breathing (AB) using surface electromyography (sEMG). abdominal muscle is including the Rectus abdominis (RA), External oblique (EO), Internal oblique (IO), and Transversus abdominis (TrA) was measured at the end of inspiration and expiration using rehabilitative ultrasound imaging. Results: In NB, normal adults exhibited significantly greater thickness than CLBP patients in the RA, EO, and TrA (p＜0.05). In AB, Normal adults showed significantly greater thickness in the EO and TrA compared to CLBP patients (p＜0.05). Within the CLBP, AB showed significantly increased thickness in the IO and TrA compared to NB (p＜0.05). Within the NA, AB significantly increased thickness in the IO and TrA (p＜0.05). Conclusions: This study was confirmed that there was a difference in the change of muscle thickness according to the breathing method of patients with CLBP and normal adults. Therefore, abdominal breathing may be considered a viable therapeutic intervention to enhance abdominal muscle morphology.