Spanish Riding School First Chief Rider Johann Meixner (1895-1916) used to say about his student Richard Wätjen: "He entered the arena on two different horses and he is leaving it on only one." (Waldemar Seunig, Meister der Reitkunst und ihre Wege, 1960, 95). This compliment with humorous overtones can serve as a stimulation for reflection on the training of horses, as its implications are much more profound than its flippant tone suggests.
Obviously, Wätjen did not literally mount two different horses at the same time. What his teacher Meixner was referring to is that before a horse is fully trained, the rider often feels as if he were sitting on two different horses. In really bad cases, it can even feel as if each of the horse's legs were moving at a different tempo and in a different direction. This sensation of having two distinct horses underneath your saddle can come from at least two different issues.
The first possible reason is a certain lack of connectedness between the horse's hindquarters and his front end. The rider feels as if he had one horse behind him and a different horse in front of him, while he is sitting in a low spot in the middle between the two, as in a hammock. That feeling is created when the horse's hind legs are so far out behind himself that they do not support or lift the horse's back, and they thus do not support the rider's weight. They can remain unflexed, since they are out of reach for the rider's leg, seat and rein aids in this position. Unflexed hind legs result in a high croup and a jarring gait, as their stiff, extended joints do not absorb the impact of the legs on the ground. The lack of support from these dragging and pushing hind legs leads the horse's back to sag, which creates the above-mentioned sensation of sitting in a hammock. Another consequence is an excessive elevation and inversion of the horse's head and neck.
Any attempt to use the reins or even the seat will make the situation worse, as these aids cannot reach the hind legs until the calf has brought them more underneath the body. Instead they would simply increase the inversion and the hollowing of the back.
The horse's rib cage feels narrow in these moments. There seems to be no place for the rider's leg, and if he has not yet acquired an excellent seat, the horse seems to "repel" the rider's leg, which then shows a tendency to slip too far forward. The only way to unite the two seemingly severed halves of the horse is to bring the hind legs into a position in which they can provide the necessary support and lift for the horse's back, and where the rider can flex them with his seat and rein aids.
It is with his calves that the rider induces the hind legs to catch up with the rest of the horse. By nudging the horse's rib cage behind the girth, when the hind leg on the same side is about to lift off, the calf aid stimulates the horse's abdominal muscles to contract and to draw the hind leg underneath himself. (Cf. E.F.Seidler, Die Dressur diffiziler Pferde, 1846, 223, translation: TR: "The flexor muscles of the hind legs are coordinated with the abdominal muscles by branches in the abdominal cavity; as soon as the calf or spur touches the abdominal muscles, the horse increases their tone and hence the forward swing of the leg.")
This line of reasoning shows that the corrective process has to start with an adjustment of the rider's seat. The leg has to be brought into a position where it can feel the horse's side, and where it can communicate with the horse. At the same time, this leg position enables the rider to sit in balance, in self carriage, which allows him to ride with an independent seat, i.e. the horse's motion does not lead to involuntary, uncontrollable compensatory movements of the rider's hands, legs, shoulders, or head.
Once the rider has firmly grounded himself with his heels underneath his seat bones and his calves resting lightly on the horse's sides, he can start asking the horse to bring his hind legs more forward underneath himself. As soon as the horse begins to respond, the rider can feel the hind legs arrive under his seat bones and in his hands. The horse’s back is starting to make contact with the rider’s seat, and the hind leg is beginning to seek contact with the rider’s hand via the bit, enabling the rider to communicate with him through his seat and rein aids.
However, if the stirrups are so long that the rider's knees are almost straight, the rider loses the suppleness and independence of his seat, and the pelvis tends to tilt forward, lifting the seatbones off the saddle. Such a rider cannot have his horse "on the calf" (German: am Schenkel), since the calf is either not in touch with the horse at all, or it is gripping the horse's sides. If the horse is not "on the calf", he is not "on the seat" (German: am Kreuz) either, because the hind legs are too far out behind for the seat to access them. If the rider is hollowing his back, his seat bones are not in touch with the saddle, which also makes it impossible for them to communicate with the horse's hind legs. - And if the horse is neither "on the calf" nor "on the seat", he cannot possibly be "on the bit" (German: am Zügel) - even if his head is vertical.
There is another possible application for the image of riding two different horses. Just as the horse can break up into a front half and a rear half, the rider will find that the horse's right side behaves differently from his left side, due to the innate asymmetry that is inherent in every living organism. In the traditional technical equestrian terminology, this falls under the heading of straightness/crookedness. Every single horse with no exception is slightly weaker on one side than on the other. The weaker hind leg escapes more or less towards the side, rather than stepping straight towards and underneath the center of gravity. This causes a more or less pronounced incurvation of the horse's spine towards the same side. E.g. a horse whose right hind leg is weaker than the left will step slightly towards the right with his croup every stride. This causes a rotation of the entire pelvis towards the right, so that the left hip is slightly behind and higher than the right one.
Since the right hind leg does not step underneath the center of gravity, but towards the right of it, and hence does not support the body mass sufficiently, the left hind leg will not have enough time to reach far enough forward. The left hind leg will therefore take slightly shorter strides, which can look as if the horse were lame in some cases. As soon as a competent rider straightens and balances the horse, this "lameness" disappears completely.
As the left hind leg touches down too early, it spends relatively more time on the ground behind the vertical than in front of the vertical. In practical terms, the left hind leg thrusts noticeably more than it carries, making it stiff and reluctant to flex its joints, which makes the horse feel stiff throughout the entire left side of his body. It will also make the left hip look and feel higher than the right. The rider will feel in most cases that the horse is seating him towards the right, because the horse back is lower on the right than on the left: the rider is actually sitting on an incline.
The left hind leg not only thrusts more than it carries, it also thrusts more than the right hind leg, which leads to a heavier rein contact on the left side, while the horse often will not approach the right rein. This usually happens in conjunction with the horse's left shoulder drifting towards the left. Many riders involuntarily compensate for this uneven feel by carrying their left hand higher and more forward, while pulling their right hand back and down onto their thigh in an attempt to create a more even feel in both hands. Needless to say that the only thing that will accomplish an even rein contact is to straighten the horse, i.e. to align the horse's hips and shoulders correctly in front of one another on the track that the rider has chosen to ride.
This natural crookedness that I have just described has certain consequences for the horse's performance. I will list some of them below, still assuming that the horse is hollow right/stiff left. For horses who are hollow left/stiff right, things are exactly opposite.
This list can serve the dressage rider as a checklist in determining the horse's hollow and stiff sides. This is an enormously important point, because in the practical training of the horse, the rider has to adjust his aids to compensate for this crookedness, in order to overcome the asymmetry and make the horse ambidextrous over time. Achieving functional straightness is one of the most fundamental demands in training horses, because a crooked horse will never be able to develop impulsion, self carriage, or lightness, not even to mention collection. What is even worse is that a crooked horse is laterally and longitudinally unbalanced and will therefore not remain sound in the long run, as any imbalance creates stiffness and bracing which translate into unnecessary wear and tear on joints, tendons, and ligaments.
- All his right turns will tend to be larger than his left turns. I.e. he will drift out of any right turn by falling over the outside shoulder and going against the rider's outside knee and thigh. Conversely, he will fall into every left turn, by falling onto the inside shoulder.
- He will tend to overbend laterally when riding on the right rein, creating a bulge, as it were, at his left shoulder.
- He will tend to counterbend when riding on the left rein, sometimes locking his jaw on the inside.
- He will tend to cut corners on the left rein by falling onto his left shoulder and leaning into the turn.
- He may be difficult to turn away from the wall on the right rein, giving the rider the sensation as if the horse's shoulder were stuck to the wall, so that the head and neck may turn in, while the horse is still continuing to follow the wall.
- When you are on the center line or on the quarter line, he will tend to drift towards the left with his entire body.
- When you ride transitions on the center line or on the quarter line, he will fall towards the left with his shoulder, and/or to the right with his haunches in all transitions.
- In transitions to the halt, the left hind leg will tend to be out behind.
- On the right rein, he will tend to show a faulty haunches-in, because his croup will tend to fall in against the riders's inside calf.
- On the left rein, his croup will tend to drift out of each turn, against the rider's outside calf.
- In the shoulder-in right he volunteers the bend, but it may be difficult to get his shoulder to leave the wall.
- In the shoulder-in left, it is easy to get the correct angle, but it is more difficult to achieve the correct bend.
- Haunches-in and half passes appear to be easier on the right rein than on the left.
- In severe cases, the horse may not want to canter on the left lead initially.
- When you lengthen the strides in the trot, the horse may frequently break into the right lead canter.
Compensating for the horse's asymmetry means that, among other things, the rider has to give different aids for turning right than for turning left. In right turns, he may have to shift his weight much more towards the inside hind leg, while using his outside rein and thigh to frame the shoulder and the base of the neck. This prevents the horse from breaking in front of the withers, turning his head and neck sideways, while still continuing on the straight line with the rest of his body. The inside calf may have to prevent the inside hind leg from falling in, which may require the rider's inside leg to be placed further back than usual.
In left turns, on the other hand, the horse tends to fall in with too much weight placed onto the inside shoulder. The rider may have to compensate for this by shifting his weight onto his outside seat bone and stirrup, while driving the inside hind leg well forward and underneath himself. His inside thigh and rein may in addition have to prevent the horse's shoulder from falling in, while his outside leg may have to be placed especially well back in order to prevent the haunches from drifting out. Since the horse is not bending enough through his rib cage on the stiffer side, the rider sometimes has to rotate his own hips and shoulders much more into the turn in this direction in order to obtain the correct degree of bending. Experimenting will reveal the correct amount necessary.
When riding on the center line or quarter line, the rider will have to keep his weight a little more towards the right, while driving the left hind leg underneath himself with his left calf, so that the horse stops bulging his shoulder and ribcage towards the left. The left rein may have to frame the base of the neck, so that the horse's shoulder cannot bulge to the left and the horse stays connected throughout his entire body.
In the shoulder-in right, the rider may have to think of riding a leg-yield - with a very straight neck - in order to succeed in moving the horse's shoulder away from the wall. Due to his natural inclination, the horse will then give the rider the necessary lateral bend. In the shoulder-in left, on the other hand, the rider has to concentrate on obtaining a good lateral bend to the inside, and the horse will most likely add the necessary angle on his own.
In the half pass to the right, the rider has to make sure that the shoulders are moving forward-sideways enough, while preventing the haunches from moving sideways too much. Otherwise, the haunches will start leading very quickly. In other words, the rider has to think of riding a shoulder-in, when practicing the half pass to the right. In the half pass to the left, by contrast, the rider has to work especially on obtaining both the correct angle and bend, since the horse's natural inclination will be to show a counter-shoulder-in rather than a half pass.
The more ambidextrous the horse becomes in the course of his training, the more similar the rider's aids can become for each side, until they are practically identical for both directions. The famous French master D’Auvergne wrote that “the horseman with all the perfection of his art spends his entire life correcting this imperfection”, i.e. the crookedness. Until then, the rider is sitting on two different horses who require different aids, depending on whether he is riding on the right or on the left rein.