The Equine Back: Core strength, flexibility & balance (Part 2 of 3)
The previous post covered a fair bit about the back’s structure, bones and the issues of carrying a rider. Part 2 will discuss more about the function of the soft tissues and groundwork exercises and part 3 will address asymmetry, ridden exercises, and my personal favorite, cavaletti.
Musculature
The muscles of the vertebral column can be divided into those running deepest next to the spine, including the multifidus, and those nearer the surface, including the longissimus and iliocostalis. The deepest multifidus muscles run along 2 or 3 vertebrae each, overlapping all the way and connecting the vertebrae to provide support, stabilization and motor control. They have a lot of innervation so give the feedback that keeps track of spinal position and motion. The more superficial muscles are larger, less innervated and provide gymnastic motion - extension, rotation and lateral motion of the spine. As we covered in Part 1, the interlocking of the vertebrae means that the spine doesn’t really have the ability to bend laterally without also rotating, so these movements require the entire spine, and very little bending at any one single joint.
As well as these muscles that run along and above it, the spine is supported by the ventral muscles running beneath it (flexors) including the abdominal muscles and the sublumbar muscles (iliopsoas muscles). By finding an equilibrium between the two sets of muscles the horse is able to move efficiently by holding the spine in enough tension to support a rider and transfer power from the limbs. The pelvic stabilizer muscles such as biceps femoris and the gluteal muscles help with balance and power transfer from the hind legs and are essential for collection and jumping.
Finally the thoracic sling muscles, such as the trapezius and pectorals, hold the forelimb onto the trunk, and hence when the forelimbs are on the ground can affect the position of the trunk.
If only one side of the thoracic sling is active, the position and straightness of the shoulder is affected. Muscle tension through both sides at the same time lifts the withers and sternum, and helps create an uphill horse, lifting the weight off the forehand and rocking it to the hind end.
The thoracic sling is also anchored to the rib cage and used in breathing. This is fine when the horse is still, but when the horse is cantering, for example, he must breathe in time with his stride, and hold his breath when he jumps. Imagine then the problem of a horse trying to relax and not ridden in an regular rhythm.
Groundwork exercises
There’s a lot of support in the research for using groundwork exercises to strengthen the back and mobilize the joints both before introducing ridden work to prepare for carrying the weight of the rider, and throughout the career, particularly after injury or time off. They help to improve strength, self carriage, balance, flexibility and the stability needed to collect or jump.
Injured or weak back muscles often do not self-correct and need to be specifically targeted or the horse will attempt to find other ways to compensate, usually by overusing the opposite side, increasing their own asymmetry rather than addressing it. Groundwork exercises can build these muscles back up. Similarly stiff joints and the spinal impingements can often worsen due to continued contact if the joints are not adequately opened and stretched, and range of motion maintained. In the more advanced horse these exercises can improve balance and power needed for collection or jumping.
Groundwork exercises can be roughly divided into three types: mobilizing the joints (horse yoga), activating and strengthening core muscles (horse bodypump) and improving dynamic balance (horse pilates). All three are important for a healthy horse. A young horse that hasn’t yet carried a rider, or a horse recovering from injury, would benefit greatly from building up his muscle tone and spinal alignment first but should be careful not to push it too far. At the other end of the scale a horse competing at high-level dressage will need to continue to build these muscles unmounted, but will need to increase the difficulty of the exercises to really challenge his muscles and balance.
Mobility (Stretches)
When a horse is challenged to stretch his spine it opens up the spinous processes and reduces the risk of impingement, and builds the small multifidus muscles that control and stabilize the spine, but often become wasted or uneven as they are not easily activated.
It’s common when doing these exercises that a horse find one side easier than another, and that’s OK, that’s partly why we’re doing them. Better to stay within the range of motion the horse can achieve correctly, then push him too far and encourage him to cheat by stepping or tilting his head. Keep an eye that his ears stay level, and accept that his flexibility, strength, balance and symmetry will improve with repetition. It is not normally worth forcing a horse into a position using manual pressure, as the horse needs to use his own muscles in order to strengthen them, and you risk pushing the horse beyond his current comfortable level of movement if you force it yourself. As with yoga, each stretch should be slow and relaxed, and aim to hold the end position once it’s achieved for a few seconds.
Using a carrot stick or other favorite bait, the horse can be asked to follow the carrot and do the following stretches.
Firstly, start with the stretches which stimulate flexion of the neck muscles, work on his rounding and abdominal muscles and extend the spine, opening up the processes.
Using the carrot he should be tempted to:
1) bring his chin to his chest,
2) bring his chin down to and/or between his knees and
3) bring his chin down to and/or between his fetlocks.
Start by aiming just to ask the horse to reach towards these positions, and then with a bit of practice, you’ll be able to go further into the stretch, for example moving his chin between and beyond his knees rather than just towards his knees. If necessary having a helper put a hand on the noseband will encourage the horse to keep his head straight, but remember to tempt him rather than pull him into position.
The second type of stretch are the lateral bending exercises. These show up asymmetry and further challenges the spine stabilizing muscles and the horse’s rounding and bending muscles. These can be tested by asking him, by following you with his nose, to one side and then the other, from the front to reaching backwards and downwards to:
4) bring his chin to his girth,
5) bring his chin to his flank and
6) bring his chin towards his hind fetlock.
It may be helpful to stand next to the horse and ask him to reach around you to encourage an even bend through the neck and spine. These exercises can be very revealing as without the added complications of a rider, and with the motivation of a carrot or other treat, it is much easier to see if there is a marked difference between the left side and the right. If you have a helper it can be useful to have them stand at a safe distance behind the horse, ideally on a stool, to see if the horse bends evenly through his body to both directions. If you’re not sure if there’s a difference then they’re probably isn’t, but it helps to take a photo of each direction to help compare them. Occasionally, you’ll see a horse who tries to keep his body straight and just use his neck on one side, but is happy to bend his entire spine in the other direction. This is the type of sign of injury or soreness from saddle fitting or ridden work that may need further investigation and is worth highlighting to your vet in the first instance. Every horse will however prefer one side to the other, particularly if he’s not been challenged to build these muscles before. An uneven ability to each side but with similar technique is not necessarily any cause for concern and should improve with practice as these exercises will greatly increase his range of motion. The horse may initially attempt to “cheat” by stepping around to face the carrot that he’s reaching for. It is not worth over-correcting this, after all it’s a fairly efficient solution to the problem of needing to stretch and wanting to reach the carrot. Just patiently put him back into position and start again, using a wall or second person to help hold his hind end still. Once he realizes which behavior wins the carrot, he’ll be more compliant in future and eventually you’ll be able to work in the field, and won’t need to keep lining him up with the wall.
There are entire books on carrot stretch technique, and they give you an insight into the most accurate targeted activation of specific muscles, but be encouraged that if your horse is moving under his own muscle power whatever you’re doing you will not be hurting him. Even if your technique is different from the next person’s, or doesn’t target the muscles you had in mind exactly as accurately as it could, your horse is still benefiting from doing a stretch.
Balance
When a horse is forced to keep his balance against a pushing hand or due to a lifted leg, he must work his core muscles correctly to maintain his position, just as we would in a sit up, pull up or push up. Young horses can even struggle to keep their balance when one hoof is lifted, and this can be interpreted as irritability at having hooves maintained when often it is just anxiety combined with a lack of muscle tone and experience with this sort of exercise.
If the stretches listed above are combined with a lifted hoof the horse must work to keep his balance, further activating his core muscles and improving his muscular control. This increases the difficulty of the exercises, so should only be introduced once the horse is already comfortable with the stretches, and is used to having his hooves picked out.
A hand pressed on the horse’s shoulder or chest for a few seconds will force him to work his core muscles to maintain his balance. You may not see him move as you press, but if he’s working correctly you should notice him rock forward again once your hand is gone.
At the other end, gently pulling on the tail to one side then the other can force the horse to resist using (and building) his pelvic stabilizer muscles. The pelvic stabilizers are the muscles that allow the power to be efficiently transferred from the hind legs, and help to keep the horse balanced and off his forehand. As with the chest press, the aim of this exercise is not to move the horse, but to encourage him to activate his muscles to keep his balance and resist the movement.
Strength
For further strengthening work of the core muscles, you could look to sternal lifts and “butt tucks”.
If you run your hand, pressing quite hard, along the sternal ridge that is the central line running underneath the horse between his forelegs, past the girth, and back towards the back of his stomach, you should see the corresponding parts of his back lift as he tightens his core muscles. In a less toned horse the difference is less obvious you should be able to see some effort from any horse. The amount of pressure required varies, particularly the first time while he works out what you want. You’ll know when you have it right. Rest assured that you are not hurting the horse, particularly if he hasn’t yet responding by moving away from the pressure.
Activating the sub-lumbar and abdominal muscles to tuck the hind end under is an excellent strengthening exercise but can take a bit of trial and error. Stroke up the spine from the top of the tail with your thumb until the horse lifts his back, engaging his hindquarters. In an advanced horse you (and a friend) can do this at this same time as lateral bending and/or the thoracic lift. As with the previous exercise, you will be able to spot a reaction when you get it.
In the very strong advanced horse you can combine these exercises with the balance exercises above, by lifting a hoof.
Source: Sian Townson
Please note that this site constitutes discussion of athletic development and performance, and does not give clinical advice.