The majority of horses I see have compromised/ weak thoracic sling muscles to some extent affecting the entire biomechanics of the horse. Especially in the halt, an often overlooked or even called ‘boring’ excercise, I observe a lot of disbalances in this area.
So why does this matter? Because the proper function of the sling muscles is essential in achieving overall (artificial) balance, which in turn is necessary for obtaining/ keeping a good health for working horses.
Unlike humans, horses don’t have a bony connection (collarbone) between its front limbs and torso. They rely on strong muscles which act like ‘slings’ responsible for the suspension of the chest between the horse’s two front limbs and lifting its thorax. The thoracic sling is made up primarily of the serratus ventralis thoracis muscle, which in turn is intimatily linked to the external oblique, and is furthermore assissted by the pectoral muscles which also have connections to the brachiocephalic and omohyoid muscle. So a proper contraction of these muscles will result in a lift of the torso and raising the withers to at least the same hight as the croup or even higher. Lacking a proper contraction will result in a downhill motion on the forehand. There are multiple causes why so many horses have issues in this area:
- Feeding / grazing posture (natural asymmetry)
Our domesticated horses primarly eat from the ground. In ‘wild’ nature, horses don’t only graze. They also browse. A lot! They eat from trees, bushes and so on. When observing, we can find that if horses are given the opportunity to browse, they usually take a different position: they contract the sling muscles and as a result the front limbs square up much more.
So when horses don’t get the opportunity to browse, they’ll spend most of their time in a ‘grazing position’ in wich horses naturally put more weight on the front limbs.. They do this by choosing 2 different positions:
- Leaning over the shoulders. The sternum and superficial pectoral muscles are pushed down and forwards into the shoulderblades with the front feet in a backwards position.
- Bracing the frontlegs. The frontlegs are placed in a forwards position to ‘brace’ and blocking the weight that is pushed into the shoulders.
Most horses have a combination of those positions: one front leg is often in a forwards bracing position and one front leg is usally in a more backwards position. This natural assymetry is often also refered to as ‘grazing foot’ and can cause issues like high heel low heel syndrome which in turn has complications for the entire biomechanics of the shoulder and its intimate connections. However, it also happens that both front legs are in the same position. Especially in foals we can observe them bracing forwards with both front legs in order to graze. So grazing ALL the time will lead to weak sling muscles. Which doesn’t necessarily has to be a problem if we’re not trying to ride/ train our horses. But since we do, feeding from the ground only is not ideal.
A lot of horses have dents in the shoulder/ pectoral area. The height of the torso of the horse often resembles with the height of fencing, gates etc. So the area is prone to any form of injury.
A lot of horses are bred for fancy front leg action and extreme flexible necks, interfering with the horse’s capability to balance itself properly. As I mentioned before, we can now observe foals that have difficulty grazing as their front legs are simply too long and they can’t reach the grass properly. So in order for them to do it, they will compensate the entire torso in a down and forwards motion.
There is a lot of talk and literature about engaging the hindlegs, riding the back of the horse, controlling the head/neck position of the horses, engaging the abdominals but there is little said about the importance of the thoracic sling in all this while yet it is all interconnected.
So let’s elaborate on this. The horse is a ‘rear-wheel drive’ with the hindlegs driving and directing the front legs. However, if the the shoulder is dropped down and pushing the sternum forwards, the energy and weight of the horse is centred and blocked in the front-end. So the hindlegs simply can’t perform their task properly as there is NO space for them to step towards to. It will literally ‘hit a wall’. So what will most horses do? Increasing the extension phase of the hindlegs resulting in backwards forces, affecting the biomechanics of the back and disbalancing energy throughout the body. Apart from back problems, this often results in issues like being 'girthy', tilting the head, bracing the jaw, rotating the pelvis the backwards, rotate the hipjoint or even the hocks to name a few. In the halt, it can even result in locking patella’s as the ‘backwards’ energy has to go somewhere and when not in motion, the horse can’t push the energy away, but will have to lock it in the body and often does so in the stifle joint.
Therefore, the thoracic sling is crucial for in restoring (artificial) balance. If the sling muslces contract properly, the sternum, shoulder and whithers will lift up. The base of the neck gets supported and the neck comes up to a more horizontal position with the poll as highest point. This lift in front will create space for the hindlegs that now have the freedom to step forwards restoring the balance between flexion and extension. The increased energy (trust) from the hindlegs will create a vertical force which the back muscles will coordinate. It is only then that the horse’s back can carry a rider with minimal effort and maximal coordination and balance. From that point, collection is nothing more than a refined control over this energetic cycle of forces. Horses can start moving in self-carriage and lightness.
Now, it’s important to note that the above is susceptible to anatomical and biomechanical variations. In general, a high crouped horse will have more difficulty with lifting the thoracic sling than a whither high horse. This is exactly why high crouped horse are suitable for sports like racing or endurance as it allows them to make short and fast strides and the horses mainly have to move in a straight line. But when doing dressage and even jumping to some extent we need to create this artificial balance for the horse to be able to properly carry our weight as we also ask them to bend to the left and right. Remember, circles are the hardest and most unnatural excercise for the horse!
So how can we improve the working of the thoracic sling for our horses? As with all my blogs I can’t give you detailed training advice for you and your horse in your specific situation straight from paper. However, here are some general tips:
- Think about REWIRING THE MUSCLE MEMORY OF THE HORSE. We’d like to change from a natural balance with most weight on the forehand to an artifical balance with more weight to the hindlegs. It’s important to remind ourselves that the horse doesn’t see the purpose of this. Because they’re not made to ride. They don’t see why their natural balance is a problem for their biomechanical health if we ride them. They just deal with the consequences by compensating. For them, it’s not a conscious process that they’re naturally on the forehand. So to change this, we have to make its muscle memory conscious of using different muscles for natural balance. And therefore, its not something we can create by mechnical aids only. It is creating awareness and changing patterns in your own body first and foremost, giving the right example. We need to adress the brain. So that the brain will give signals to a different set of muscles for balance. By doing so, you’ll notice the balance of your horse in natural grazing position change as well. Not because they think of it consciously, but because the muscle memory has changed and now it’s the most efficient and logical way for them to balance.
- BREATHE. The thoracic sling is closely related to the thorax which has a big and direct influence on the heart and lungs of the horse. So if we’re training/riding too tense, we can literally squeeze out the breath of our horse. If you’re riding, ‘breath’ through your legs. If you’re working from the ground, use your own thorax as well. Breath. Lift. If will make a diffference.
- Work on ESSENCE. Balance is not a trick. It’s not about getting the legs square in a halt. It’s not about mechanically trying to lower the horse’s neck/head position. It’s about playing with and coordinating energy. Then the legs and a natural neck/head position will follow as result. And this differs from horse to horse.
- ADRESS THE CAUSES, NOT THE SYMPTOMS. Horses are movers by nature. So if your horse doesn’t want to move forwards properly, he/she has a good reason for it. So there is no point in giving a lot of leg aids to push him/her forwards as this will only create more blocks and tension throughout the body.
- OBSERVE & PALPATE. You can quite easily palpate the superficial pectorals and even the serratus ventralis thoracis. Palpate the pectorals on along both sides of the sternum. How do they feel? Tight? Loose? Consistent smooth surface? Or does it feel stringy? Or are there even holes or dents in there? You can take your hand all the way through between the front legs and continue palpating around the girthing area. Is your horse sensitive? Girthy?
- MANAGEMENT changes. Start feeding your horse from different positions or build a ‘food’ station by making a small hightened stair where the horse has to place its frontlegs in order to reach the food.
Renowned pathologist Sharon May-Davis recommends to put one haynet a day up high to balance out the torso and front feet. However, be careful to start putting up a haynet really high from the start with horses with SI problems and don’t force them to eat it. Just give them the possibility and observe and experiment with different heights.
So look at your horse. Feel your horse. Ask for help or guidance if you’re struggling. You’re horse will be thankful.