“Through the back” is one of those things that means different things to different people. I often get the feeling that to many competition judges, it just means that the horse’s head is down with a round neck. But there is actually much more to it.
The Problem
If the horse is not “through the back”, his back is tight and rigid. The rib cage tends to be narrow instead of expanded, and the back is usually dropped instead of raised. The gaits are uncomfortable to sit in this case. There's no wave-like swinging motion, but instead, it feels more like a jackhammer. If the horse is not through the back he is generally either inverted or the neck is short.
Horses can go with their head down and a round neck, but without having a connection from back to front and to the reins. It feels like there's nothing in your hands because the back isn’t transmitting the impulses that are coming from the hind legs.
The Goal
For me when the horse is moving through the back, it means that the back and the withers are raised and the ribcage expands and fills my leg and seat. I feel the energy flowing from the hind legs through the back and along the whole top line to the bit and then back. It is like a stream of water or electricity that flows from the hind legs along the spine that you receive in your hands with a connection also in the other direction. If you close your fingers on the reins you can send impulses into all four legs. There is a back-to-front connection, a front-to-back connection, a left-to-right connection, and a right-to-left connection. The energy has to be able to reach every corner of the body without skipping any part of it, and without exiting somewhere. There's also a top-down connection from my body, my weight, through the horse's legs into the ground. The movement of the horse's back feels like it's swinging up and down, like a wave that you can ride.
Once you have felt it you know what I'm describing and you will never forget it. It leaves a very powerful impression. As the hind leg pushes the horse into the suspension phase of the trot the horse's body lifts up. His pelvis, back and withers move up and forward which creates a wave that lifts the rider. Upon landing after the suspension phase, the horse will descend again and the rider swings down together with the horse’s back. Next time you ride, try to feel the wave of the horse’s back swinging up and down and try to accommodate it so that you're synchronized with it.
This swinging connection is not something that is automatically present all the time. It's something that needs to be created by removing blockages and patching up leaks so that the energy circuit can be established and the back is able to move freely in all directions. Once you have established it, it’s not guaranteed for life. For instance, if the horse loses balance, he will brace his legs against the ground and his back against the rider, and the supple, swinging motion disappears. Or if the horse suddenly gets scared and tense he will brace his neck and tighten his back. The better trained the horse is, the more advanced he is, the more reliable this connection through the back will become.
How to Achieve It
The Horse’s Biomechanics
Lifting the withers is the result of the engagement and flexion of the hind legs and the abdominal muscles engaging at the same time.
The first step is to bring the inside hind leg more under the body. Enlarging the circle, shoulder-fore, or shoulder-in are excellent tools for this.
The next step is to flex this hind leg by riding a turn, corner, volte, or a turn on the haunches. Half halts and down transitions work as well.
Flexing the hind leg and supporting the body mass is followed by extending its joints and pushing again. If the grounded hind leg is out behind the body, it can only push it forward onto the forehand, but it can’t lift it up, and the back will drop as a consequence. If the hind leg touches down close enough to the center of gravity, it can lift the body up in such a way that the back and the withers lift up as well.
The Rider’s Seat
In order for the horse to be able to lift his back and withers the rider may have to make a little room with her seat. If the seat is static it will push the horse’s back down towards the ground as a result of gravity. This makes it more difficult for the horse to lift his back than is necessary, and horses with a weak back may not be able to do it at all.
The rider can make the horse’s job much easier by semi-actively accommodating the upward motion of the horse’s back with her seat. The reason is that when the horse’s abdominal muscles contract to pull the hind leg forward they lift the back at the same time. So if we ask the hind leg to take a bigger step we need to allow the back to rise higher. Otherwise, the horse’s back bumps into the bottom of our pelvis like a ceiling and has to drop back down again, which cuts the stride of the hind leg short.
When you watch horses move you can see that horses whose neck is elevated too much and whose back is dropped, usually step short behind. This is a bit of a chicken-and-egg situation. If the hind legs step short, the back will collapse under the weight of the rider, and the neck will lift up with a contracted top line. Or, conversely, if the rider sits too heavily on a weak back and/or artificially elevates the head and neck with her hands, the back collapses and the hind legs are prevented from engaging.
Only when the back and withers are lifted and the top line is stretched, can the hind legs engage optimally (and vice versa).
How to Influence the Movement
In the sitting trot you can create space under your pelvis in such a way that you're swinging a little higher than you normally would in the sitting trot, but not as high as in the rising trot. You may have to support yourself more with the insides of your knees for a step or two and use the momentum of the horse’s back to create a little air pocket under your seat. If the horse has enough impulsion, he will lift his back higher and stay in touch with your seat. The hind leg will engage more as a result as well. If your seat loses touch with the saddle, you can apply a driving aid with your inside lower leg or touch the horse with the whip on the inside when the inside hind leg is in the air to increase the engagement of the inside hind leg and the lifting of the back and withers. When it works you feel like you're swinging up, but you are not leaving the saddle because the saddle is coming with you and the horse's back is lifting into it.
This can become a game. How much can I lift my pelvis without losing touch with the horse’s back and with the saddle? Can I get the horse to lift his back more by making room and driving? Explore that. How much can I rise? How much do I need to rise? Do I need to drive or not? When you consistently create this little space underneath your seat every time you drive, the horse will connect the dots and respond to a lightening of the seat by engaging his hind legs more and increasing his energy output. Then you get the effect of a driving aid, but without driving, merely by creating space.
You can explore this on simple arena patterns, like a 20m circle, or whole-school, or even on a trail ride. Once you get the feel for it, you can apply it in all the lateral movements as well. Depending on whether you accentuate the upward swing when the inside or outside hind leg is in the air, you can increase the reach of one individual leg. In lateral movements, this means you can accentuate either the sidestepping aspect or the forward aspect of the movement.
What goes up must come down. After you have created more space under your seat to encourage the horse to reach farther under the body with a hind leg you could accentuate the downward motion with your seat for a stride or two in order to flex the joints of this hind leg more.
The same principle can be applied in the canter as well. You can make the horse’s canter bigger and rounder by increasing the upward motion of your pelvis here and there when the outside hind leg is on the ground and the forehand lifts up. I wouldn’t do it every stride, otherwise, it gets too noisy, but you can do it two strides in a row, and then stay passive for a couple of strides, and repeat it as needed. You may have to add a driving aid here and there to create a bigger jump.
Summary
The swinging movement and energy connection that are the result of a horse working properly through the back create a feeling you will never forget. Choose exercises and arena patterns that encourage the horse to engage and flex his hind legs, and remember to use your seat in a dynamic way that supports the horse’s movement, so that he is able to lift his back, engage his hind legs, flex his hind legs, and push off again with them in a forward-upward direction.
