H&C caught up with dressage rider and trainer Keith Robertson for some tips on shoulder-in.

“In these photos, I am riding two of my more advanced horses. Wild Storm is an 11-year-old Irish x Hanoverian chestnut gelding working at Prix St George level, and Korenbloem Fleur de Lis is a bay 11-year-old Dutch Warmblood Mare working at Advanced Medium.

What is shoulder-in? In the British Dressage rulebook, shoulder-in is defined as follows: The horse is slightly bent round the inside leg of the rider. The horse’s inside foreleg passes and crosses in front of the outside leg; the inside hind leg is placed in front of the outside leg. The horse is looking away from the direction in which he is moving. Shoulder-in, if performed in the right way, with the horse slightly bent around the inside leg of the rider, and at the correct tracking, is not only a suppling movement but also a collecting movement, because the horse at every step must move his inside hind leg underneath his body and place it in front of the outside, with lowering his inside hip.

It also states: a) The additional aim of lateral movements is to develop and increase the engagement of the quarters and thereby also the collection. b) In all lateral movements the horse is slightly bent and moves with the forehand and the quarters on two different tracks. c) The bend or flexion must never be exaggerated so that it impairs the balance and fluency of the movement concerned. d) In the lateral movements the pace should remain free and regular, maintained by a constant impulsion, yet it must be supple, cadenced and balanced. The impulsion is often lost, because of the rider’s preoccupation mainly in bending the horse and pushing him sideways. e) At all lateral movements the side to which the horse should be bent is described as the inside. The opposite side is the outside.

The basics Shoulder-in is a movement that I would introduce to horses’ training plans from a relatively early stage, once the horse is balanced in all three gaits, attentive to the aids and has mastered the leg yield under the rider. Most of our horses begin shoulder-in from the age of four or five as a suppling exercise, and later as an exercise to aid engagement and collection. Usually performed in trot, shoulder-in first appears at Elementary level. In shoulder-in, the horse's footfalls are on three tracks. The shoulder-in is the basis of all lateral work seen in the higher levels and the cornerstone of gymnastic exercises; it is used to supple and balance the horse and encourage him to use his hindquarters.

Riding shoulder-in down the long side Before you start, make sure you can balance independently (i.e. you are not using the reins to steady yourself), your horse responds to your leg, that he bends correctly through corners and on circles, and that he is working into both reins with a consistent soft contact. Once you have established the basics, you can start to include shoulder-in in your work. Establish a forward rhythmical trot and use a corner or small 10m circle in the corner to collect and balance your horse (see photo) in preparation for shoulder-in down the long side. This will ensure you come into the shoulder-in with the correct bend.

As you leave the corner, position the shoulders to come slightly off the track as if preparing to continue on your 10m circle again. Keep your inside leg on the girth to maintain inside bend and signal to your horse that he is not to leave the track. Turn your shoulders slightly in the direction you are bending your horse. Your outside rein supports the horse’s shoulder and prevents him from moving in off the track. Your inside rein should maintain a light contact; avoid pulling or holding the horse’s head to the inside with the rein as you will either overbend the neck in relation to the body, or cause the horse to come in off the track. It is the riders inside leg that creates and maintains the bend. Your outside leg is a little behind the girth and remains passive to encourage correct bend; it should only become active if you feel the horse’s quarters swinging out. Once you have established the shoulder-in on the long side, your horse should stay in the movement until you tell him otherwise.

Straighten the horse before the corner so you can ride a balanced correct corner. In competition, shoulder-in is required on a straight line between two markers and not round corners. Here Keith demonstrates a correct three track shoulder-in.

Common problems Loss of impulsion It is common when introducing new movements for horses and riders to approach tentatively or for the rider to be over-controlling in an attempt to produce the movement at all cost. Allow the horse to travel forward confidently to the contact to maintain energy within the movement. If you feel the horse is too forward return to walk and maintain the exercise rather than being too strong with the rein or hand.

Head tilting Head tilting can easily become an issue within lateral movements, commonly as a response to the rider being stronger with one hand or attempting to deal with a greater degree of stiffness on one side of the horse’s body. Firstly look at yourself to check you are can provide equal pressure through both reins and that any rein being used is moved smoothly. With a stiffer horse, return either to the exercise in walk initially or use some leg yield to help improve the horse’s suppleness.

Lack of bend in body This can also be the result of horse stiffness or an overactive rider’s inside rein, which will also create excessive neck bend. Return to your start point and begin the exercise again. For a stiff horse it is a matter of following the guidelines above. If the rider is considered to be at fault again check the contact. The inside rein may be too strong creating the excessive bend, however if the outside rein does not provide sufficient control to the outside of the horse’s body the same mistake can result.

Too much angle This fault can again can be rider or horse oriented. Generally caused by a stiffer side on a horse or an overzealous rider. This can however also occur with inexperienced or young horses trying to please, so take your time when trying to work out the exact cause.

Incorrect bend Can be the result of a genuine misunderstanding between horse and rider or may stem from a horse's resistance in a movement it is finding difficult to achieve.

Return to the exercise in walk and enlist a friend or mirror to help correct you before returning to the trot.

Rider crookedness Created frequently by riders desperately trying to ride the movement strongly from their body or simply not having developed the control required to maintain an effective basic position during lateral work (of course we didn't manage to get a photo of this!). Try to relax into the movement checking you are sitting evenly on both seat bones and keeping your shoulders level. Again enlist a friend to tell you what looks right and wrong.

Rider pushing quarters out rather than bringing shoulders in This is very common and happens when the rider’s inside leg comes too far back behind the girth, over focusing on the ‘sideways’ element of the exercise. You must imagine the inside leg sends the horse forwards along the track, whilst the outside leg is positioned slightly further back to guard the quarters from swinging or being pushed out. This will almost feel like your normal canter aid position initially so don’t be surprised if your horse mistakes it as such at some point. Aim to maintain even bend through the horse from nose to tail thus ensuring the suppling part of the exercise is achieved. Good luck with your shoulder-in!"