Effects of 8-week TRX exercise program on bowel habits and gastrointestinal symptoms in competitive male swimmers aged 9–13: a randomized controlled trial

Background Exercise-related gastrointestinal complaints are frequently reported in young athletes; however, evidence regarding the effects of resistance-based training modalities on bowel habits is limited. The aim of this study was to investigate the effect of an 8-week TRX program on bowel habits and gastrointestinal system of male child swimmers. Methods Thirty-two prepubertal male swimmers aged 9–13 years (age: 10.87 ± 1.16 years; height: 148.0 ± 34.0 cm; weight: 40.82 ± 8.3 kg) were voluntarily enrolled in the study. Participants were randomly allocated to either the TRX or control group. Both groups were evaluated using the Bristol Stool Scale and a questionnaire assessing defecation habits before and after the 8-week TRX exercise program. Results Descriptively, the proportion of participants who postponed defecation decreased in the TRX group, whereas an opposite trend was observed in the control group. No clear change in stool form was detected between groups. A mixed-design repeated-measures ANOVA revealed a significant group × time interaction for total gastrointestinal symptom scores (F(1,30) = 13.73, p = 0.001, partial η²=0.314), indicating that TRX training led to greater improvements compared with the control group. Conclusion These findings suggest that TRX training may represent a safe and potentially beneficial exercise approach for improving gastrointestinal comfort in young athletes. Clinical trial number NCT07464509-11/02/2026.