Parents of young children being treated for encopresis sometimes think it strange that their child likes to runs around before pooping. One parent said, "My son often needs to run up and down the hallways to make a bowel movement." In fact, there is nothing strange or unusual about this at all. As I say in my book, The Ins and Outs of Poop:
"Exercise is important (especially when treating encopresis!) because it directly affects the movement of stool. Our large intestine works better when we are active. Children (and adults) frequently experience the urge to poop either during exercise or shortly thereafter. Children who are physically active are less likely to become constipated than those who are not." (page 50)
Exercise helps constipation by decreasing the time it takes food to move through the large intestine thereby decreasing the amount of water the large intestine absorbs from stool. Aerobic exercise, like running, is especially helpful because, by speeding up breathing and heart rate, it helps stimulate intestinal peristalsis.
Therefore, provided that your child's laxative and liquid intake is sufficient to make his stool softer than normal ( applesauce or pudding), you might want to encourage your child to run around for a few minutes before sitting to try to poop.