This exercise is, in particular, suitable for teaching both horse and rider to maintain a constant rhythm and a cadenced canter. The horse repeats its movements calmly. This is excellent preparation for jumping and is suitable for all horses.
Using poles that are 2 metres long is even better. It will allow you to test your ability to keep the horse straight. If the horse drifts from the line’s median axis, it will soon exit the exercise. Using 4 metre poles makes it more difficult to notice this.
If the horse tends to rush or accelerate, place the line’s last landing spot 3 strides from the school’s wall. One should remember that - in most cases - simply imagining a 2.50 metre wall at the end of the line is sufficient for solving this problem.
Start with one pole, and if all goes well, add another every time you repeat the exercise.