Indeed, horses are amazingly well constructed. Their ability to store and reuse energy in their tendons, aponeurosis, and even muscles are so efficient that they can practically achieve the second half of the stride using the energy created during the first half. The phenomenon is called "stretch-shorten contraction."  It applies to the legs but also 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 outcomes of stretching and relaxation. Understandably, such has been our ancestors' belief, but an advanced understanding of equine locomotion exposes a different picture. Ease, effortlessness, and consequently soundness result from optimum storage and use of elastic strain energy. The whole system depends on the muscles' capacity to ensure optimum tension of the tendons and aponeurosis. There is no room for release and relaxation. It is all about nuances in muscle 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 the initiative. 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 workers. When they realize that we guide their brains toward a comfortable and effortless way of using their bodies, they are mentally involved and take the initiative.

The paradigm shift from relaxation to energy is significant but wonderfully efficient. This is the horse's comfort zone, the language where the 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, General 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 exert 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 of 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, despite 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 gaits' kinematics was 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? Should we update their teaching to actual knowledge of equine physiology? This is a no-brainer and a fascinating journey. Indeed, horses are amazing creatures and understanding how their body works is an incredible journey. You will change the way you sit; you will change the way you think, but as you evolve from obedience to cues to a direct conversation with the horse's brain, you will also change the orders. The master is the horse. He is the master in your mind and heart, and you are the Maestro who creates and works with the master.

Jean Luc  

Science Of Motion 2015