What is the drive line? In this excerpt from my book, I will explore the drive line and how important it is for you to understand where it is on the horse’s anatomy and how the horse responds to it when working at liberty, or when the horse is loose in the round pen. This, of course, is not a real, physical line; it is an imaginary vertical line which determines by body language the direction the horse will go in relation to your position in front of, or behind, the line. Think of the line more as a zone, not a hard line. Remember that every horse is different so the line’s position may also be different. Once you have the line firmly positioned in your mind, communicating with your horse will become easier, smoother, and more productive.