One of the mares I ride has a tendency to drift right as she jumps, so I developed a tricky little exercise for her. We always do a lot of work in counter canter, straightening her and making sure each rein is as good as the other.
She can rush thoughtlessly towards fences so after working over some canter poles I slowly built up to a placing pole to and upright and then a landing pole. This prevented her rushing and made her think about the jump, her positioning, and her getaway. I made sure to use wooden poles here because she can be careless and send light poles flying across the arena. Once she had mastered this set up, I added tramlines before the placing pole and after the landing pole.
The first time, the mare backed off the exercise, unsure of how to tackle it. But we clambered through. Now that she had been through once, I could tackle the straightness issue.
She easily cantered through the first tramlines, but needed careful correction by opening the left rein and closing the right leg over the jump.
The beauty of this exercise was that I could approach in both directions and off both canter reins so could keep her on her toes and stop her anticipating the exercise and rushing.
Of course I had to hop off a few times to replace poles, especially the lightweight tramlines, but after a few goes on each rein the mare felt much straighter and was making a better shape over the upright.
Tramlines are so useful and could be put into almost any exercise to encourage the horse to stay straight, and to help the rider position themselves correctly. This mare will definitely be seeing more of them!