Jockey's Handful is a term used to describe the amount of control a jockey has over a horse during a race. It refers to the combination of the CROP, REIN, and REINS that a jockey uses to guide the horse. The CROP is a short whip used to encourage the horse to move faster, while the REIN and REINS are straps attached to the bridle that the jockey holds in order to steer the horse. Together, these three items give the jockey a great deal of control over the horse during a race.