A person who out of choice or due to mental disabilities, rocks back and forth in a disturbing manner. These are often laughed at by people of the general public if the jockying is so vigorous the chair collapses or the jockey smashes his/her back against the back of the chair
Hey look, that retard's a complete chair jockey!
Someone who only works in the office at his desk. Usually used to define someone who used to do field work, but due to promotions and age, only sits in a chair and watches others work for him.
Will and I used to inspect bridges together for the state, but ever since he turned 40 and got that promotion, he's nothing but a chair jockey now, barking orders to everyone out working in the field.