Jean Luc Cornille & Chazot
Indeed, horses are amazingly well constructed. Their ability to store and reuse energy in their tendons, aponeurosis and even muscles, is so efficient that they can practically achieve the second half of the stride just by using the energy created during the first half. The phenomenon is called, "stretch-shorten contraction." It applies to the legs but also to the entire body. Muscles are composed of fibers capable of contractions and tendinous components storing and reusing elastic strain energy. Muscles can store and use energy even in the absence of tendons. We have been told that ease and effortlessness were the outcome of stretching and relaxation. It is understandable that such has been the belief of our ancestors but advanced understanding of the equine locomotion exposes a different picture. Ease, effortlessness and consequently soundness, are the result of optimum storage and use of elastic strain energy. The whole system depends on the capacity of the muscles to ensure optimum tension of the tendons and aponeurosis. There is no room for release and relaxation. It is all about nuances in muscles tone, contractions and compensatory contractions.
This is where our partnership with the horses became astoundingly subtle. If we try to stretch and release the muscles we hamper their ability to optimize the elastic energy stored in their tendons and aponeurosis. Instead, if we understand what effortlessness is about, the horses respond and take initiatives. Once they realize that we don’t try to fit them into our view of their world but instead respect their world, they ease their protective reflex mechanisms that simplistic equitation labels as behavior. This is the partnership that I am talking about. Horses are ethical worker and when they realize that we guide their brain toward a comfortable and effortless way of using their body, they are mentally involved and take initiatives.
The paradigm shift from relaxation to energy is significant but wonderfully efficient. This is the horse’s comfort zone, the language where partnership is real. Respect always has engendered more willingness than submission and respect of the horse commences with our ability to evolve. Classic authors have shown the way. In 1949, Gneral Decarpentry talked about the concept of storage and reuse of energy. It was at this time simplified at the level of compression of the joints before their extension. “The degree of elevation of the body during the moment of suspension will depend likewise on the vigor of the effort of the hind legs, and consequently on the amount of previous compressions of their joints.” (Academic Equitation-1949).
Decarpentry also hinted on the production of horizontal and vertical forces. “In the elevated gaits, the thrust of each hind leg displaces the horse’s body simultaneously forward and upward. An effort of horizontal propulsion and one of vertical projection can be distinguished in this thrust. “ (Academic Equitation) It was believed at this time that the propulsive activity of the alighting hind leg commenced as soon as ground contact. Based on such belief, the deeper the hind legs engaged under the horse body, the greater the ability of the supporting hind leg to produce upward force. The problem is that, even if such antiquated belief is still emphasized, the alighting hind leg does not exerts a propulsive activity at impact. Instead, the alighting hind leg resists gravity and inertia forces decelerating the horse’s body. This initial sequence of the stride is named the “braking phase,” in reference to the hoof pushing on the ground in the direction of the motion as if it was braking. In cursorial locomotion, this initial sequence of the stride lasts 45% of the stance. After the peal vertical, which is the instant where the hind limb is acting vertically onto the ground, the hoof exerts on the ground a force opposed to the direction of the motion propelling the horse’s body forward.
The net effect of the hind leg propulsive activity is a force in the direction of the motion. The thrust generated by the hind legs travels forward through the thoracolumbar spine where it is converted at the level of the vertebrae into horizontal and vertical forces. “An initial thrust on the column is translated into a series of predominantly vertical and horizontal forces which diminish progressively as they pass from one vertebra to the next”. (Richard Tucker, Contribution to the Biomechanics of the vertebral Column, Acta Thoeriologica, VOL. IX, 13: 171-192, BIALOWIEZA, 30. XL. 1964) The modulation between horizontal and vertical forces that our ancestors attributed to the hind legs is in fact created by the muscular system of the thoracolumbar column.
The reality exposed by modern technology differs widely from what we have been taught. A legitimate question would be, “Is it possible that our ancestors could have been wrong for thousands years?” The answer is another question. Would it be possible that our ancestors could have figured the incredible sophistication and complexity of the equine mechanism without modern technology; accelerometers, plate form measurements, high speed video, the mathematical equation measuring inverted dynamics? Of course not but, in spite of primitive science, some came incredibly close.
Just remember that until Edward Muybridge invented the technology of photographic series at the end of the 19th century, even something as simple as the kinematics of the gaits were not soundly understood. Muybridge (1830-1904) was contemporary with François Baucher and Gustave Steinbrecht.
Should we apply their principles at the letter knowing that their understanding of the horse physique was not the functioning of the equine physique exposed by advanced research studies, or should we update their teaching to actual knowledge of the equine physiology. This is a no-brainer and a fascinating journey. Indeed, horses are amazing creatures and understanding how their body works is a startling journey. You will change the way you seat; you will change the way you think but as you evolve from obedience to cues to a direct conversation with the horse brain, you will also change the orders. The master is the horse. He is the master in your mind and in your heart and you are the Maestro that creates and works with the master.
Science Of Motion 2015