Horse races were an important and prestigious component of the Olympic games and the breeding of racehorses required an important financial investment. Wealthy men and women owned racehorses and the winner of a race would have his or her name entered on the list of victors. The female figure on the above vase might very well be the owner of the winning horse.
In the horseback riding race or keles, the jockeys were young boys who rode without the use of a saddle or stirrups. They employed only reins connected to a bronze bit in the horse's mouth and a small riding crop. cf S. G. Miller, Ancient Greek Athletics, Yale, 2004, pp. 77-79.