Background <p>Colonoscopy is a widely used diagnostic and therapeutic tool for colonic diseases and serves as the preferred screening method for colorectal cancer (CRC). A common difficulty during colonoscopy is the looping of the colon, which can result in patient discomfort, prolonged cecal intubation time (CIT), and the need for auxiliary maneuvers. This study aimed to evaluate the efficacy and safety of using an abdominal binder during colonoscopy performed by trainees.</p> Methods <p>This randomized, double-blind, sham-controlled trial was conducted at a tertiary center. Participants were outpatients aged 20–80 years undergoing elective colonoscopy. They were randomly assigned to either the abdominal binder (AB) group or the sham binder (SB) group. The primary outcome measured was cecal intubation time. Secondary outcomes included the need for manual abdominal compression and postural adjustments during the procedure.</p> Results <p>A total of 211 participants were enrolled in the study. The median CIT was significantly shorter in the AB group compared to the SB group (728 s vs. 774 s, p = 0.008). Additionally, the AB group demonstrated a significantly reduced need for manual abdominal compression (p ≤ 0.001) and postural adjustments (p = 0.01). The requirement for abdominal compression decreased by 40% (95% CI 27.7–52.9%), while the need for postural changes was reduced by 9.4% (95% CI 1.9–88.7%).</p> Conclusion <p>The use of an abdominal binder during colonoscopy performed by trainees significantly reduced cecal intubation time and minimized the need for ancillary maneuvers, such as manual abdominal compression and postural adjustments.</p> Graphical abstract <p></p>