What are normal movements (motility) of the digestive tract? How may altered motility lead to symptoms? Disorders affecting the motility of the digestive tract may be self-limiting, occurring only for a brief period as in acute infection of the digestive tract causing diarrhea. They can also be more longstanding and persistent as in irritable bowel syndrome (IBS). IBS is associated with a variety of symptoms, particularly abdominal pain and an irregular bowel habit.