Dressage movements may include circles, figures of eight, and crossing the diagonal and all paces walk, working trot, collected trot, extended trot, canter, a halt, and a rein back.
Depending on the level of restraining aids (seat and hands), the leg can also ask for an increase in impulsion, for collection, or even for the rein back.
This is to teach the horse to keep his haunches straight, and to help with moving them backward in the rein back, which is taught after the haunch flexions.