Response to the waspish ghosts of theological thinking.

Part VIII

 

Half Halt





“A long habit of not thinking a thing wrong, gives it a superficial appearance of being right.” (Thomas Paine)


The American author provides the second best definition of the half halt. The greatest thought about the half halt belongs to the man who influenced practically every riding school in Europe, Fran?ois Robichon de la Gueriniere. This classic author regards the half halt as an action slowing down forward motion. La Gueriniere believes in the virtues of a correct halt but warns against the damages that abrupt halting might induce on a horse improperly built or highly spirited. “The advantages derived from a well-executed halt are to collect a horse, steady his mouth, head and haunches and to make him light in the hand. However, as beneficial as the halts may be when they are executed at the right moment, so may they be harmful when used improperly.” (Ecole de Cavalerie, 1731)


La Gueriniere regards the half halt as a measured action where the horse is only held slightly more in hand without being completely halted.” At the time of la Gueriniere (1688-1751), equine research studies were like a paradox. The drawing of the horse skeleton exposed at the Faculty of Sciences in Paris  depicts a horse assembled like a dinosaur who could not even execute one step forward. Yet, in 1752, Joseph Bridges diagnosed for the first time lameness caused by changes in the distal sesamoid bone as navicular disease. The name of his study was No Foot No Horse.


There are today as many definitions of the half halt as people talking about half halt. However, the general consensus regards the half halt as a way to shift the weight back over the haunches. The concept of backward weight transfer is in contradiction with actual knowledge of the equine physiology. In her 2002 PhD. Thesis, Sophie Biau wrote, “This notion that still in use today does not have any scientific meaning from the perspective of the equine biological mechanism.” Balance cannot be achieved shifting the weight backward as half halt proponents suggest. Instead, balance can only be achieved controlling how the forces generated by the hind and front legs are transmitted and converted forward through the spine. The theory of half halt shifting the weight backward is another simpler interpretation of the feeling given by the horse converting, through the thoracolumbar spine, the thrust generated by the hind legs into vertical forces that resist gravity and therefore allowing the forelegs to produce greater upward vertical impulse.


In the light of conventional beliefs, this last sentence must look like Chinese. This is because conventional beliefs are severely off. The general consensus emphasizes that the hind legs are propelling the horse’s body upward and forward as soon as impact. In reality, at impact and until about 45% of the support phase, the hind leg on ground contact is decelerating the horse’s body. This sequence of the stride is referred to as the braking phase. The hoof is slightly sliding and digging into the ground exerting a force in the direction of the motion. The joints of the supporting hind legs are folding resisting attraction of gravity and inertia forces.


The same action is created by a human hiking downhill. Knee extensor muscles decelerate one’s body at impact through a muscular work known as eccentric contraction. The decelerating phase of the horse’s supporting hind leg lasts from impact to the instant where the hind leg is acting vertically onto the ground. This instant is referred to as pic vertical. After the pic vertical, the hind leg propels the horse’s body forward moving backward behind the horse’s body. The net effect of the hind legs propulsive activity is therefore a force in the direction of the motion. “The hind legs provide both support and propulsion. The net effect is a force in the direction of the motion.” (H. F. Schriver. DVM, PhD. D. L. Bartel. PhD. N Langrana. PhD. J. F. Loice. DVM. - 1978)


The involvement of the hind legs into balance control is primarily a decelerating action resisting gravity and inertia during the first half of the stance. (The stance, like the support phase, describes the sequence of the stride where the hind hoof is on ground contact.)

 The propulsive activity occurs when the hind leg is behind the hose’s body and therefore is much more a force in the direction of the motion than upward. This is why measurements effectuated in 1996 demonstrated that the forelegs were creating more vertical impulse than the hind legs. “In horses, and most other mammalian quadrupeds, 57% of the vertical impulse is applied through the thoracic limbs, and only 43% through the hind limbs.” (H. W. Merkens, H. C. Schamhardt,G. J. van Osch, A. J. van den Bogert, 1993).


This brief video sequence which is an abstract of the video we presented at Immersion 3, illustrates the braking and pushing phases of the hind and front legs. The horse's polo wraps are painted in red during the braking phase (deceleration) and in green during the pushing phase. For clarity the video is preented here frame by frame.

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Simply looking at the way the hind legs effectively functions, the deceleration promoted by Monsieur de la Gueriniere is much closer from actual knowledge of the equine physiology than the up and backward hands action shifting theoretically the weight back over the haunches. Basically any half halt pretending to shift some of the weight backward is a senseless gesture trying to accomplish a phenomenon which does not exist.


One may argue, but my horse rebalances himself in response to my half halts. The horse might effectively figure that the rider’s cue is about weight on the bit and either restricts his motion or shortens his neck to ease the weight on the bit. Talented athletes might even figure that increasing the decelerating phase of the hind leg allow them to enhance their balance control. Such eventuality could be used to support the thought than upward and backward hands actions might be a valuable educating system. The reality is that even if a horse figures proper use of the hind leg decelerating phase in response to such a cue, it is more likely that the horse will do so protecting any existing back muscle imbalance. One can easily imagine the stresses that the decelerating phase of the hind legs is inducing on the hocks of a horse as twisted in the spine than the specimen presented in our previous discussion.


Since I described a rein action commonly regarded as half halt, one might theorize that one’s half halt works because one does it differently. There are million versions of half halt. The problem is not that one gesture is better than the other. The point is that the backward shift of the weight that all these half halts try to achieve simply does not exist. This is not the way the horse achieves balance control.


For centuries, horses have been able to perform beyond their talents in spite of the sole help of ill adapted or approximated riders’ insights. For these horses, the price has always been lameness. The ghosts, who venerate classical equitation like a cult, convince themselves that our ancestors’ were infallible and that their horses did not have issues. Well, the introduction of this discussion refers to Joseph Bridges who in 1752, in the heart of the classical era, diagnosed horses with navicular syndrome.


A horse executes a performance protecting existing muscular imbalance, morphological defect or weaknesses. Monsieur de la Gueriniere was aware of this problem. His teaching advises adapting the training approach to the horse’s morphology and temperament. The classic author describes five morphological and emotional flaws rendering a horse vulnerable to the physical demands of an abrupt halt. Out of concern for these horses, la Gueriniere refers to the half halt as a milder education teaching the horse to master his body deceleration. However, even if better than abrupt halt, the half halt that la Gueriniere suggested was only improving the horse’s chances of figuring how to properly coordinate his physique. Today’s knowledge greatly furthers the horse’s odds. With sound understanding of the hind and front limbs kinematics as well as the vertebral column mechanism influencing limbs kinematics, concepts hinted by the greatest became easy to understand, apply and even improve.


How a half halt, such as the one suggested by Monsieur de la Gueriniere (which was in line with actual knowledge of the equine physiology), has evolved into pulling actions attempting to shift the weight back over the haunches, which is in contradiction with actual knowledge of the equine physiology, raises a question mark. Isaac Asimob proposes a brilliant response, “My ignorance is just as good as your knowledge.” As long as the horse has been able to compensate, ignorance has allowed as much of a result in the show ring as has knowledge. The difference is that the horses of the ignorant have to have the joints of their body injected on a regular basis. By contrast, knowledge protects the horse from harm, suffering, and lameness.


Jean Luc Cornille

(In the next installment about half halt, we will talk about the work of the horse’s vertebral column, the forelegs and the neck.)

 

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