Dissecting the Seat - Part 5: Deep Seat vs Light Seat by Dr. Thomas Ritter

What is a deep seat?

You have probably all heard that one of the qualities of a good seat is that it is deep. But what does that mean? For me personally, a deep seat is a seat with a low center of gravity and the largest possible area of support. This lends the seat stability and it allows the rider to feel the horse with her entire body, which is why the old masters used to say that the rider should sit “in” the horse, rather than “on” or “over” the horse. A seat with a high center of gravity and a small support base, on the other hand, is unstable and doesn’t allow the rider to feel the horse very well.

A low center of gravity and a large support base also allow the rider to connect her weight through the horse’s legs to the ground. The seat is then secure and balanced, which leads to a sense of feeling at home on the horse’s back and to relaxation.

Heavy seat

One potential pitfall is that perhaps some riders think that in order to sit deeply they need to ride with extra long stirrups or that they need to sit very heavily on their seat bones. However, stirrups that are too long overextend the rider’s hip, knee, and ankle joints so that they can no longer function as shock absorbers. The support base becomes smaller when the legs are too extended, the rider feels less stable and less independent in the saddle. The femurs tend to rotate outward, and the hip joints tend to lock up. The rider is then no longer able to allow the horse’s back and rib cage to move freely in all directions because she herself lacks the necessary freedom of motion in her leg joints.

When the rider sits heavily on her seat bones, she will prevent the horse’s back from lifting in the long run, which prevents the hind legs from engaging. The horse breaks into two pieces and falls onto the forehand. The connection between the hind legs and the bit through the spine is then severed. The rider’s pelvis and legs need to be able to accommodate the movement of the horse’s rib cage in all directions and to shape it by increasing or decreasing certain movements at any given time. So you could say that the seat has to be deep AND light at the same time. Sometimes it is necessary to create a small space under our pelvis and our seat bones so that the horse can lift his back and engage his hind legs more, which leads to an increase in roundness and throughness. This requires the rider to get support from below the seat bones, i.e. the inner thighs and knees in addition to the bottom of the pelvis and the seat bones.

Hovering seat

The opposite potential pitfall is that riders may want to sit lightly at all times and end up in a permanent 2-point seat, or hovering above the horse. This usually leads to the horse extending his hind legs and pushing the croup up, so that he ends up dropping his back and falling on the forehand as well. Sometimes these horses step under their body with their hind legs, but they don’t flex them. As a result, they may lean onto the bit or invert. If they are short backed or a little croup high, they may forge or the hind legs step on the heels of the front legs because the overloaded front legs don’t lift up in time to get out of the way of the landing hind leg. When the hind legs flex under the weight, the front legs have enough time to lift and make room for the landing hind leg.

Biomechanics of the stride

In each stride the hind legs lift off and swing forward, touch down and flex under the weight, and push the body mass forward by extending their joints. The rider’s seat has to allow all three by flexing and extending her hip, knee, and ankle joints to allow the wave like up and down motion of the horse’s back. In addition, the pelvis has to be able to move in all three dimensions in order to accommodate the movement of the horse’s rib cage and back in all planes. In a neutral seat the rider’s joints flex and extend exactly as much or as little as the horse’s back and rib cage move up and down, forward and back, and left and right. The rider neither increases nor decreases any aspect of the stride.

A heavy seat, in which the entire body weight of the rider bears down all the time, accentuates the flexion of the grounded hind leg at first. But it also keeps it grounded and makes it return to the ground as soon as possible. This has the effect of slowing the hind legs down and preventing them from lifting up and engaging, so that the strides become shorter and the hind legs no longer support the back. The back collapses under the rider’s weight, and the horse inverts or shortens the neck.

A hovering seat does the opposite of the heavy seat in that it never asks the hind legs to flex. On the positive side, it allows the back to lift, but on the negative side, the hind legs become stiffer because they stay more and more extended. This results in rough gaits because there is no shock absorption by the hind legs if they don’t flex, and the back won’t lift and swing if the hind legs don’t act as springs. It can also result in forging and injuries to the heels of the front legs. But it can also lead to tripping or short, minced strides, if the toes of the hind legs drag on the ground.

So what do I do?

A good strategy is to start with a neutral seat that is deep, balanced and supple, not fixed in any one position, with all joints flexing and extending just enough to accommodate the horse’s natural back and hind leg movement. Observe the quality of this movement. What do you notice most? What is good about the walk, trot, or canter that you are riding? What would you like to improve? Is it elastic, springy, round, energetic, or jarring, hard, flat, lifeless? If you are not sure which aspect to change, you can always experiment by accentuating one of the three phases of the stride and observe whether the horse feels better or worse to you. In lessons I often ask students how the horse feels before and after an exercise. Many riders find it very difficult to put their feelings into words. But if you try to describe precisely what you are feeling, you train yourself to feel more clearly and to reflect on what you are feeling. This becomes a very valuable diagnostic tool.

You can accentuate the liftoff and forward swing of the hind leg by not merely letting the horse lift you up, but by supporting yourself more with your knees for a split second and letting your pelvis swing up a little higher than the horse would lift you if you were completely passive. This can be further supported by driving with your lower leg on the side of the hind leg that is lifting off. If you drive a split second before the hind leg lifts off, you can accelerate the hind leg if it’s too slow.

You can accentuate the flexion and weight bearing of the hind leg by letting yourself sink down more and sending your energy and your weight through the flexing hind leg into the ground. This creates shorter and higher steps during the release of the seat aid. If the horse is rushing, you can stay down a split second longer before you allow the horse to lift you up again. This will slow the tempo down. It can be further supported by stepping into the stirrup on the side of the landing hind leg and/or by a half halt on one of the reins.

You can accentuate the extension of the grounded hind leg by engaging your back muscles, sending your weight and your energy down into the ground through the extending/pushing hind leg. You can give a brief push with both knees when the hind leg is on the ground behind the vertical. I also let my pelvis swing up and forward when I want the hind leg to push more. That way I don’t suppress the lifting of the horse’s back in a lengthening and I direct the energy upward as well as forward so that the horse doesn’t fall onto the forehand.

Conclusion

One important thing to keep in mind is not to do everything at once, all the time. But to select one aspect of the stride that you want to improve, accentuate it for 2-3 strides, then return to neutral and observe the effect of your aid. Based on your observation, choose another aspect to accentuate, or repeat the last aid, if it wasn’t enough yet. Sometimes it makes sense to build sequences of aids, e.g. accentuate the lift off/engagement of a hind leg for 2-3 strides, then accentuate the flexion for 2-3 strides. This creates more elastic gaits.

Or accentuate the flexion of the grounded hind leg for 2-3 strides, then accentuate the lift off/engagement. This will lead to shorter, higher, more energetic strides, which can evolve into a passage over time.

You could also engage a hind leg for 2-3 strides, then accentuate the extension of the grounded hind leg for 2-3 strides. This creates more powerful strides and a more solid connection from back to front if a horse tends to hold himself back.

Dr. Thomas Ritter
www.artisticdressage.com