Effect of Sitting Posture on Transversus Abdominis Thickness and Trunk Muscle Activity During a Valsalva-Based Simulated Straining Task in Healthy Young Adults
Background/Objectives: Defecatory straining requires coordinated abdominal-wall and lumbopelvic muscle activity to generate propulsive pressure. This study investigated whether sitting posture alters ultrasound-derived transversus abdominis (TrA) contractile behavior and trunk surface electromyographic (EMG) activity d...