Ella Fitzgerald - "First Lady of Song", "Queen of Jazz", and "Lady Ella", was an American jazz vocalist. In 1993 she had to have both of her legs amputated below the knee due to the effects of diabetes. Her eyesight was affected as well.
A good jazz rhythm doesn't try to be anything special. It knows what it's supposed to do, and it goes with the flow. If it tries to speed up or tries to force itself onto others, it fails to be what it's supposed to be, which is a good jazz rhythm.