Background: Diastasis of Rectus Abdominis (DRA) is a frequent problem that affects women during pregnancy and postpartum. The study aimed to investigate the effectiveness of static and dynamic plank exercise on Inter-Recti Distance (IRD) in postpartum women. Methods: This semi-experimental study included 30 postpartum women with DRA who were randomly divided into static plank (N=10), dynamic plank (N=10) and control group (n=10). Exercise groups implemented the plank exercise three times weekly for six weeks in Sari, Iran from April to May 2023. Ultrasound imaging was recorded to measure IRD in three locations, center of umbilicus (reference point), three cm above and three cm below umbilicus. The analysis of covariance (ANCOVA) was used to compare the effect of static and dynamic plank exercise on IRD. Results: IRD significantly decreased in static (29 mm vs 27/4 mm, P=0.001) and dynamic (30.1 mm vs 27 mm, P=0.001) plank groups after exercise. IRD did not significantly differ between static and dynamic groups at post-test (P=0.420). However, the percentage of the change was greater in dynamic (10.33%) compared with the static (5.51%) group. A significant difference was observed between the dynamic and control groups (P=0.001). Conclusion: The findings revealed that both types of plank exercise could cause narrowing of IRD in postpartum women. However, based on the percentage of change, incorporating additional movements such as abduction and rotation in dynamic plank, which could produce more muscle activity, yielded greater reduction in IRD compared with static plank.
