Shoulder-in: What is it and what are its benefits?
The shoulder-in is a movement that could merit a book in and of itself. When we think of the cornerstones of good dressage training, the shoulder-in immediately pops to mind.
The 18th century French riding master, Francois Robichon de La Gueriniere, is generally credited as having invented the shoulder-in in 18th century. He is quoted as saying it is the "alpha and omega of all Dressage exercises."
The United States Equestrian Federation (USEF) defines shoulder-in as follows: “This exercise is performed in collected trot. The horse is ridden with a slight but uniform bend around the inside leg of the rider maintaining cadence at a constant angle of approx. 30 degrees. The horse’s inside foreleg passes and crosses in front of the outside foreleg; the inside hind leg steps forward under the horse’s body weight following the same track of the outside foreleg, with the lowering of the inside hip. The horse is bent away from the direction in which it is moving.” [USEF Rule Book DR111]
In dressage competition, it first shows up at 2nd level and is found all of the way up through Intermediare 1. Even though we first see shoulder-in at 2nd level, we should begin training the movement well before we show that level. We can and should begin the process of teaching the beginnings of shoulder-in to young horses early in their training. In this article, we'll study what shoulder-in is, what are the aids for shoulder-in, what are its benefits, what are its variations, and what are common problems(and their solutions) found when riding shoulder-in.
In previous articles, turn on the forehand and leg yield were discussed. These exercises are both prerequisites for the shoulder-in. Once a horse is well versed in turn on the forehand and leg yield, it is time to begin training the shoulder-in. While the turn on the forehand and leg yield have little gymnastic value and are used mainly for educational purposes, the shoulder-in has immense gymnastic value and thus should be practiced in some form by horses at almost any level of training. If you'll recall, the turn on the forehand, teaches the horse to move sideways. Leg yield teaches the horse to move forward and sideways. Shoulder-in takes the leg yield and adds in the oh so important element of bend. Adding the element of bend gives the shoulder-in the gymnastic values of strengthening and suppling. Because the shoulder-in has bend, instead of the inside hind leg sweeping straight sideways, the inside hind leg will step up farther under the center of gravity. As the inside hind leg steps further under the horses body, the hock takes more weight making this a weight lifting exercise for the horse. Additionally, when the shoulders are moved in sufficiently, the front legs will cross suppling the horse's shoulders. The shoulder-in also supples the rib cage of the horse, as they are taught to move away from the inside leg pressure.
We can classify the shoulder-in as a 2-track movement. This means that the horse's forehand and hind quarters travel on 2 separate lines of travel as opposed to single track bending exercises like circles where the forehand and hind legs and forelegs line up perfectly. For example, when a shoulder-in along the track is ridden, the haunches will be on the track and the shoulders should be placed slightly in from the track.
What is the correct angle for a shoulder-in? As noted in the previous definition, it should be roughly 30 degrees. How do we measure that? Do we need to time travel back to eighth grade and borrow a protractor? I suppose you could, but if you don't have access to a Delorean, then you should either ride towards a mirror, if you have one, or have someone on the ground watch you or video tape you. If you are in the proper angle for shoulder-in, you should only see 3 legs of the horse, as the inside hind leg and outside foreleg should line up.
Why is the correct angle important? As discussed earlier, the inside hind leg should step up under the horses body and load more weight. If the angle goes more than the aforementioned 30 degrees, the inside hind leg will step sideways across the horse's body and not load any more weight onto it. In essence, the over angled shoulder-in becomes a leg yield. If the angle is less than 30 degrees, the engagement and weight loading of the inside hind leg will be minimized. While an under angled shoulder-in doesn't maximize weight loading and bend, it is a very useful exercise unto itself.
The shoulder-in that has an angle less than 30 degrees is called shoulder-fore. In the shoulder-fore, the inside hind leg will be seen in between the 2 front legs when seen from the front. The shoulder-fore is how you begin the training of shoulder-in with young or green horses. In most cases, the young horse will not be supple enough or strong enough to have enough bend and angle for the proper shoulder in, so we begin with shoulder-fore. Over time, the angle and bend is increased until the shoulder-in happens. The shoulder-fore is also used as a straightening exercise in the canter. Because the horse's hips are wider than the shoulders, when the horse is left to its own devices in the canter, they will most likely canter with their haunches in and their inside hind leg disengaged. Following this logic, it makes sense that the canter on both leads should be ridden in shoulder-fore ALL OF THE TIME in order to be straight.
So we now know what shoulder-in is. How do we create it? What are the aids? As I mentioned earlier, with young or green horses, we may not be starting with shoulder-in but rather shoulder-fore. That being said, the aids are the same for each. First, let's discuss how the rider should be oriented in the shoulder-in. The rider should should have their inside shoulder (inside being towards the direction of the bend) back, so their shoulders match the horse's shoulders. The rider's legs should be displaced with the inside leg forward just behind the girth and the outside leg pulled further back from the hip. The inside leg is there for the horse to bend around and the outside leg guards against the haunches swinging out. If the rider's shoulders and legs are positioned in this way, the rider should feel more weight on the inside seat bone.
Some common positional faults seen when riders ride the shoulder in are as follows: some riders will pull their outside shoulder back. This is often accompanied by the rider pulling their inside rein across the withers. The main problem here is that the horse is falling into the inside leg, so the rider twists in an attempt to prop the horse up. In addition to the rider twisting to the outside, often times we'll see the rider's legs displaced opposite in which they pull the inside leg up and back and push the outside leg forward. This will create two problems. First, by pulling the inside leg back, the rider will push the haunches out too much creating more of a leg yield. Second, this faulty leg alignment will put the rider's weight more on the outside seat bone making it impossible for the horse to bend the right way and shoulder-in is not shoulder-in without the bend!! Lastly, riders will sometimes lower their inside shoulder collapsing the hip on that side. Ideally the rider will rotate their torsos completely evenly without tilting one way or the other. Once again, this tilting can actually put the rider on the wrong seat bone.
Once the rider is in the proper orientation, then they can begin to aid for the shoulder-in. It is advisable to always start by driving with the inside leg (with rhythmical leg pressure, not a steady squeeze). If the rider turns the shoulder before adding inside leg pressure, the horse will most likely fall inwards losing their balance. The inside leg has two main functions in shoulder-in. It drives to yield the rib cage (not the haunches!) and it acts as a pillar for the horse to bend around.
Once the inside leg activates on the rib cage, the shoulders turn and BOTH reins help to bring the shoulders in. The inside rein initiates the turn of the shoulder and creates supple flexion of the poll. The outside rein holds the line of the shoulder and regulates the bend of the neck. Oftentimes, riders use only inside rein and this results in neck-in, not shoulder-in where the horse's neck bends significantly, but the torso stays straight. Once in a while, riders use too much outside rein and create a counter flexion, so the shoulder-in is lost. As you can see from the description of the aids, the shoulder-in is primarily an inside leg to outside rein movement. The inside rein and outside leg are more passive. If the horse is truly connected properly from inside leg to outside rein, the rider should be able to give a full yield momentarily on the inside rein, and the horse maintains proper angle and bend.
Once the rider has the shoulder-in properly positioned, the rider should drive for energetic strides full of engagement. We do not want the trot slowing to a crawl with hind legs dragging. Ideally, for proper engagement, the inside hock should reach to the level of the inside stifle. This is done by pushing for ground cover in the shoulder-in.
There are many different varieties of shoulder-in. The most commonly seen is riding along the track of the arena, bringing the shoulders in away from the track and leaving the haunches on the track. Again, the haunches should not swing out or it's a leg yield. Riders may also ride it on the quarter line or center line as well which is a good test to see if the horse is truly between the inner and outer aids without the support of the wall. Riders may ride it on a circle. The shoulder-in on the circle is a great suppling exercise and one I do often. A good exercise is to ride a figure eight switching shoulder-ins as you switch circles. Rider's may also ride the shoulder out or counter shoulder-in. It is the same as shoulder-in but everything's reversed. The bend is to the outside of the arena and the shoulders are positioned farther out than the haunches. This can be used to ease a horse into haunches-in and it's also a great energizer.
Some commonly seen problems with the shoulder-in have already been discussed, but I'll review them here, so there's a concise list to look back on. The most common problem seen is lack of angle and proper bend primarily caused by over bending of the neck. This neck-in doesn't create any extra weight loading of the inside hind leg or create any suppling of the shoulders. If this is a problem for you, first review the leg yield to make sure that the horse is sensitive to the inside leg pressure and then try lightening the inside rein and taking up a bit more on the outside rein to straighten the neck more. Conversely, riders can make the angle too great. If this is happening, soften the outside rein a bit and guard the hind legs with more outside leg pressure. Another fault seen, especially with young or green horses, is either loss of impulsion (pushing power) or running. Inside leg pressure can create more impulsion for the horse with lagging energy. Also, the horse that quits in the shoulder-in may need less angle for a time as they may not have the strength for a proper shoulder in yet. Running is prevented through half halts which rebalance the horse to the hind leg even going as far as doing some transitions to walk to make the point about not running. Lastly, another common problem is tilting of the poll. If the horse tilts the poll to the inside, that is commonly caused by too much pulling on the inside rein. If the horse tilts the nose to the outside, this is generally caused by the horse avoiding the outside rein contact. In general, as the horse becomes more laterally supple through their body, the tilting starts to dissipate. The poll tilting is more a symptom of a problem rather than the main issue into itself.
The shoulder-in is synonymous with good dressage training. It had multiple benefits. It supples the shoulders, strengthens the hocks and it solidifies the inside leg to outside rein connection. It can also be used to straighten crooked horses, such as those moving with the haunches in and for both leads of the canter. When you introduce shoulder-in to your horse, start with a small angle and bend to ease them into it. Chances are they will struggle a bit, but as you repeat, it should get easier and that's your cue to increase angle/bend. Dive into the shoulder-in with your horse and see what this tremendous two track exercise can do for them!