Muscle thickness of lateral abdominal muscles in sitting and standing positions during abdominal drawing-in maneuver and abdominal bracing among healthy adults

Background: Spinal stabilization exercises, such as abdominal drawing maneuvers (ADIM) and abdominal bracing (AB), are crucial in alleviating low back pain, especially in functional positions such as sitting and standing. However, few studies have investigated the contraction patterns of the lateral abdominal muscles during ADIM and AB in these daily living positions (i.e., sitting and standing). Objective: The study aimed to investigate the thickness of transverse abdominis (TrA), internal abdominal oblique (IO), and external abdominal oblique (EO) during ADIM and AB between sitting and standing positions. Materials and methods: Twenty-four healthy adults (12 males, 12 females) without low back pain or other orthopedic conditions were assessed in sitting and standing positions while performing ADIM and AB. Real-time ultrasound imaging was used to measure the thickness of the TrA, IO, and EO during the ADIM and AB. Results: Muscle thickness of TrA and IO was significantly greater during ADIM when compared to AB (p<0.05). TrA thickness during AB was significantly greater in sitting than standing (p<0.05), but ADIM showed no difference in both positions. ADIM and AB can produce contraction of the lateral abdominal muscles (LAM) in both sitting and standing positions. Conclusion: ADIM and AB can produce contraction of the LAM in both sitting and standing positions. However, ADIM can activate TrA and IO muscles better than AB. Therefore, clinicians may initially consider using ADIM to teach individuals who need core stability exercises such as low back pain.