Why might abdominal distention accompany intestinal hypomotility?

Gas and contents: in the intestine accumulate rather than emptying at a normal rate, hence distension results from gut hypomotility.

Hypomotility: means that the bowel propels its contents forward at an abnormally slow rate. This can result in excessive fluid, gas, stool accumulation, which can dilate the bowel loops, and cause abdominal distention.