Jean Luc Cornille- 10-2014

“A visually identical hind limb extension in late stance may be accomplished by only hip extensor muscles, only knee extensor muscles or any combination of these.” (Liduin S. Meershoek and Anton J. van den Bogert. Mechanical Analysis of Locomotion.)

The phenomenon is not limited to stifle extension. Many apparently identical movements can be executed with different muscular combinations. This is why a horse can be crippled or rehabilitated by the same movement. If the training is limited to the exploitation of natural reflexes, the predictable outcome is lameness. Instead, if the education guides the horse’s brain toward the muscular coordination optimally adapted to the athletic demand of the performance, the outcome is soundness. The outcome is also winning in the show ring as many superior athletes perform below their real potential due to a dysfunctional physique.

Supah is a 17.2 hand Thoroughbred gelding whose body bears the scars of a racing career. Bony proliferations and swellings are on all of his legs, especially around the front fetlocks, his front incisors are broken, his right jugular vein was occluded and there is an enormous bony protuberance on the top left side of the 9th to 10th thoracic dorsal spine at the level of the supraspinous ligament. We do not really know what caused it - trauma from a fall is a possibility, especially as he was so crippled from the track he was prone to stumble and did occasionally fall when trying to play at pasture. Whatever was the cause, it was associated with him carrying his trunk sunk between his forelegs, which severely handicapped the motion of his left foreleg. The front limb could barely move forward ahead of the vertical of the point of the shoulder. He could only turn by planting and turning around his forelegs, thus he could not run away or protect himself and was low in the herd social order. Mentally, he was not weak, but physically he could not stand his ground. 

When I first met him, Supah was lame and riding him left you with the impression of sitting on the slope of a ski jump.  I tactfully refrained from going over all his problems and simply commented that he is a kind horse – which he is. “You see why I need your help” said Betsy. “We have to restore a sound range of motion.”  I was ready to underline the magnitude of the challenge but Betsy added, “Well, if two people can do it, it is us.” Betsy is a veterinary pathologist, a researcher and a good rider. We work together at different professional levels. We both knew that manipulating Supah’s limbs would not have much result. The problem originated from a traumatized thoracic dorsal spine, supraspinous ligament and surrounding muscles. The horse had adapted to the trauma by creating a strange and restricted motion of the left front leg and consequently, his entire body. “Since he has been able to successfully recreate some range of motion, we should be capable to guide him toward a more functional and even perhaps sound locomotion.”  However, we would need active participation of his mind. We would need mental processing, initiative and even creativity. Because of his injuries, Supah would have to figure out how to coordinate his movement by using muscle combinations very different from those usually involved. It would be a challenge. The SOM approach is to prepare the horse for the movement and then let him do it. With Supah that last step of finding the solution himself was a huge one.

Betsy commented: “In spite of what he has been through, he is curious and optimistic. He is also a quiet thinker. Just to be able to move the way he does, he must have figured out some complex compensatory mechanisms, and even though his movement is mostly very bad, there are sometimes moments when it is a little better. Perhaps we can teach him better muscular coordination.” We did, and today, Supah is far ahead of our expectations. Months ago, the canter was a three legged gait. It was not walk and it was not trot, therefore by deduction it had to be canter. As he learned a better body coordination, the canter improved beyond expectations, becoming the horse’s best gait. Today, he performed flawlessly his first flying change.

It was a real flying change. It was not a lead change type of move where the hind legs are late behind. It was a real flying change, straight, clean, executed soundly during the fly period. Betsy rewarded the horse and walked saying, “The power of the mind.”  Mechanical rehabilitation by methods involving moving the limbs or releasing muscles is limited. In cases of severe damage, the structure is irreversibly altered and the rehabilitation is about guiding the horse’s brain toward a subtle, sound and efficient way to compensate. Tendon injuries for instance are in many instances irreversible. Once the fibers composing the heart of the tendon have been torn and disrupted, completely restoring clean and sound architecture is currently not feasible, although it might be possible one day with gene therapies and a better understanding of tissue microenvironment and mechanics. Until then, approaches that reduce scarring and strengthen the peripheral tissues – basically those that find ways to functionally compensate for the tissue damage, are the best way to facilitate recovery from such injuries.

A very effective approach is to teach a horse to use a different muscular coordination. However, it can only be done through respect, engagement and refinement of the horse’s mental processing. It is based upon guiding a horse’s brain toward the most efficient compromise for its body. Supah, for example, might not be capable of stabilizing the scapulo-humeral articulation at the impact of the left foreleg using the infra and supraspinatus muscles as a horse would normally do. Thus he must mentally figure out how to use different muscles for this purpose even if stabilization of the sacpulo-humeral joint is not the primary function of these muscles. Horses do this kind of compensation all the time, but immediate relief directs their choices, which is sometimes in conflict with long-term efficiency and soundness.

“Movements are generated by dedicated networks of nerve cells that contain the information that is necessary to activate motor neurons in the appropriated sequence and intensity to generate motor patterns. Such networks are referred to as Central Patterns Generators, (CPGs). The most basic CPGs coordinate protective reflexes, swallowing or coughing. At the next level are those that generate rhythmic movements. Some, such as respiratory CPGs, are active through life, but are modulated with changing metabolic demands. Others such as locomotor CPGs, are inactive at rest but can be turned on by signals from command centers.” (Sten Grillner, The Motor Infrastructure From Ion Channels To Neuronal Network.)  

Basically, the horse’s central nervous system creates movement. However, the brain will naturally execute movement protecting whatever muscle imbalance, morphological flaw, or other issue is influencing the “body state” at the instant of the effort. Excellence and soundness demands guiding the horse’s brain toward the proper activation of motor neurons in the sequence and intensity that produce correct movement.  The problem is that the Central Pattern Generators learn from each other and when they have adapted to incorrect locomotor patterns, they “sense” these incorrect locomotor patterns as normal. The concept is simplistically explained as “muscle memory.” 

However, many problems cannot be resolved at the level of the muscles; they have to be resolved in the brain at the level of neuronal activation and processing. From the outside we cannot activate motor neurons in the appropriate sequence and intensity to correct movement but the horse’s brain can do it from within. Education is therefore critical for guiding a horse’s brain toward the appropriate body coordination for its body. This is why the horse’s intelligence has to be developed very responsibly and very carefully. How a movement or exercise is done is more important than the exercise itself.  Imitation does not facilitate the kind of mental processing that the horse needs to develop. Having the horse mimic a trainer’s limb or hand movements inhibits the horse’s ability to think in terms of sophisticated body coordination as the focus is on imitating the gestures not on developing overall balance and fine control of movement. Obedience to touches, the whip or other techniques, keeps the horse’s mental processing at a primitive level. These techniques promise “dressage” because the horse executes pathetic parodies of the movements but they alter both the horse’s physique and mental processing. They damage the physique because they don’t prepare the horse’s body for the athletic demand of the performance, and they demean the horse’s intelligence by keeping the mental processing at elementary level.

The horse which stimulated this discussion was lame. He had to win his soundness through sophisticated mental processing. He was physically handicapped and had to process new locomotor pathways to compensate. Considering the extensive damage he likely had in the extrinsic muscles of his forelegs, wither, and cranial thoracic muscles, we conceived a plan to help him develop a better body coordination. Our specific goals were to reduce the load on his forelegs, correct the torsion of his thoracolumbar spine, increase the decelerating activity of the hind legs and increase the conversion of the hind leg trust to vertical forces through better coordination of the back muscles. Our hope was that reducing the weight on the front legs and educating the extrinsic muscles of the forelegs would allow greater amplitude of movement. Critical to this was to understand Supah’s mental processing of the exercises and guide him, when necessary, toward a better compromise for controlling how his body moved. Sometimes, Betsy had to change course between our monthly sessions, responding to the horse’s new tentative efforts. He is a quiet thinker. He processes, understands and tries, and his mind is often ahead of his body. We understood that developing a new body coordination is very hard and respected his limits. Some days he quickly tired from the effort and we stopped rather than push him to do it ‘one more time’. This respect and being allowed to experiment and make mistakes quickly made him confident and his understanding and interest in the work grew. In fact, in some instances we realized that his approach was a better idea that our original thought and we followed his initiative.

Supah’s progress was very slow, especially at the beginning, but it was constant, and he has physically changed in unexpected ways. He literally grew a wither in that as his muscles developed and his trunk became more elevated, the protuberance was no longer the highest point and has moved easily 5 inches further back. Betsy uses a thick and soft pad under the saddle and, as she was tacking up the horse for the training session, I joked, “Soon you will not need the pad as the protuberance will be behind the saddle.”

Once soundness was established we realized that Supah’s mind was on its way to greater goals and we continued the process. The last three months, the progress at the canter was so amazing that we were talking about the flying change. We did not decide to teach flying change, the horse showed a body coordination that allowed us to think the time to set him up to do it would soon arrive, but even so he did sooner and better than we expected. The idea was interesting as the vertebral column gymnastic during flying change would be a great way to further his body control. In parallel with his readiness for the flying change there was a clear gain in suspension and amplitude of the trot. Having come so far, we are curious to see how much further he will go in his task for excellence. Soundness is no longer a concern; now it is about sophisticated body control. It is fascinating to see a horse overcoming serious physical handicap through the development of his intelligence.

Jean Luc Cornille

2014           

 PS: Betsy just told me that ‘supah’ is New York city slang for ‘super’. The name fits him as exceptional ability and accomplishment are not only limited to those with physical talent.