The systematic way to train a dressage horse to do a walk pirouette is to start with turn on the haunches.
A turn on the haunches is a 180-degree turn done at the walk. Your horse bends in the direction of the turn. His forehand moves around his haunches until he’s facing the opposite direction. His outside hind foot and his forefeet move around his inside hind foot, which forms a pivot.
o Your horse must maintain the regular rhythm of his walk. His pivot leg gets picked up and put down each time, slightly ahead of where it was before.
o Turn on the haunches engages the hindquarters and encourages bending of the joints of the hind legs. The end result is that your horse’s body feels more packaged.
o Turn on the haunches is an introductory movement for the walk pirouette. It differs from a pirouette because it’s done from a shortened medium walk while a pirouette is done from a collected walk. Also in the turn on the haunches, your horse’s hind feet make a small circle, (about the size of a dinner plate). In a walk pirouette, your horse’s inside hind leg should be picked up and put down almost on the same spot.
The aids to train your dressage horse to do a turn on the haunches to the left are:
Seat:
Put your weight on your left (inside) seat bone.
Left leg (inside leg):
Place your left leg on the girth to promote bending and engagement of your horse’s inside hind leg.
Right leg (outside leg):
Place your right leg behind the girth to help bend your horse around your inside leg and to prevent his hindquarters from swinging out.
Left rein:
Turn your wrist to ask for +1 flexion.
Right rein:
Use your right rein as a siderein to limit the amount of bend you get in the neck.
Both hands:
Move both hands in the direction of the turn to move the forehand around the hindquarters. Keep your hands side-by-side and equidistant from your body. Think of your left rein as an opening rein and bring your right rein closer to your horse’s neck. Imagine that your hands are like the second hand on a clock sweeping around the face of the clock.
The sequence of aids are:
1. Prepare for the turn by using a “stilled seat” to shorten your dressage horse’s medium walk.
2. Bend your horse to the inside.
3. Set him up for the turn by riding in a slight shoulder-fore position.
4. Bring both hands in the direction you want his body to turn to guide his forehand around his hindquarters.
Since the two most important ingredients to train a dressage horse to do a correct turn on the haunches are rhythm and bend, preserve these qualities by introducing it on a circle.
o Do haunches-in on a 10-meter circle.
o As long as your horse keeps his rhythm, bend, and desire to go forward, decrease the size of the circle while you’re still in haunches-in gradually.
o Make the circle only as small as you can while keeping the rhythm, bend, and forward desire.