The shoulder-in is one of the most useful exercises for your horse; it supples both the shoulders and the quarters, and brings the inside hind leg under the belly of the horse which helps to engage his quarters and lighten the forehand. Of course, none of this happens if the movement is not ridden correctly.
To prepare your horse for shoulder-in
Firstly, your horse should be well balanced on a circle and able to move away from the rider’s inside leg. It is usual to begin this with leg yield, but this can make horses twisted. As an alternative either start this using in hand work or do quarters out of the circle.
In shoulder-in it is important that the horse is bent throughout his body. The degree of angle will depend on the horse’s level of training and conformation. The exercise should be ridden slowly, and in walk the steps should not be too wide or the horse’s back will become hollow. You should feel the horse’s weight remains on the inside hind, not the outside shoulder.
Shoulder-in is created in the corner so your horse should come out of the corner well balanced and in a good rhythm. You should feel as though he is offering the movement to you. If not, continue on a circle and set things up again. If the movement doesn’t go well, ride out of it and start again. It is more important to have a few very correct steps then many incorrect steps.
The rider should sit well-balanced in the centre of the saddle. It is very easy to allow your body to tip to the inside, which will unbalance the horse. Move the horse’s shoulders over by a slight movement of the hands to the inside; don’t pull the inside rein as this will block the horse.
Using light touches with the inside leg, step the inside hind leg across and use half halts to help the horse stay on the line. Once the horse understands the movement, the rider should stay quiet in the saddle, moving with the horse, and be attentive to the steps, ready to make a correction if needed.
Reasons for loss of impulsion or travelling
Too steep angle
The degree of the angle will depend on the conformation and suppleness of your horse. Have a smaller angle to start with and only ask for two or three steps. Build the number of steps and degree of angle as your horse becomes more supple.
Horse not round inside leg
In this instance the horse will brace against the rein and either drop to the outside shoulder and travel down the wall with a straight body and twisted neck, or they will step the inside hind leg forward, not across, and then they will travel forward away from the wall. Correct this by riding a very accurate circle to set the movement up again. Keep the inside rein soft and don’t use it to create either the circle or the shoulder-in.
Rider not sitting correctly, usually leaning to the inside, or tipping forward.
Not sitting correctly puts the horse out of balance; they will not be able to step sideways and the movement will travel forwards. If the rider tries to hold the shoulder-in through the reins, the horse may stay on the side but will be twisted in the neck, not bent through the body. The rider’s position should be slightly turned to the inside (hips and shoulders mirroring the horse’s hips and shoulders), closing the body towards the outside elbow to keep the balance and prevent leaning to the inside.
Horse does not bring the inside hind leg under sufficiently
This error is very dependent on the suppleness and conformation of the horse. Some horses find it easier to have a large angle in shoulder-in, others (such as a cob) may find the angle needs to be smaller and in this case the hind legs may not cross. What is important is that the shoulder-in is ridden correctly, then it will have a good suppling effect.
The horse will hollow if the steps are too big, or if the rider takes the inside rein as this blocks the inside hind. In shoulder-in the steps should be slow and unhurried; they should be small with the hind legs passing close together particularly in walk.
Left below - the horse is falling to the outside shoulder and the rider is twisted
Right below - horse is not round the inside leg, is hollow and resisting the rein.
Diane Followell Classical Dressage Trainer