I get many questions about what to do if your horse falls out of lead in the circles. The root cause of this is generally that your horse is leaning out. He can be pushing out with his front end, his back end or both. The simple fix for this is teaching them to be straight.
Most of this happens because the rider puts the horse in a situation where they are not straight. Riders think shortening the inside rein will keep the horse in the circle and not falling out of lead. In reality, shortening the inside rein causes the shoulders to leak across the straight line.
Make sure that you, as the pilot, have everything even, starting with your reins. If your horse continues to fall out of lead, then push everything into the circle similar to a side-pass – again making sure your reins are even or a little shorter on the outside rein. This will generally clean up your circles.
It is important everything goes into the circle straight, not over-exaggerated the front or back end. This can only be achieved with good body control on a horse. If you do not have it, slow down and go back to the basics. Remind your horses to move off of pressure, not into it.
Most importantly – uneven reins are the root of most evil in reining!