The “Bamboo Piaff,” Progress or Regress

When the International Equestrian Federation banished the practice of poling the horses’ front legs over the jumps, the governing body of the equestrian world showed integrity and clairvoyance. Few years later, scientific studies demonstrated that the practice was in fact, addressing the wrong end of the problem. Technologies measuring the forces produced and absorbed by the hind and front legs revealed that in most instances, faults of the front legs knocking over the top rail of a vertical originate from insufficient propulsive force of the rear legs in the early phase of the push off. “Knocking over an obstacle was significantly associated with lower hind limb acceleration peak at take-off.” (E. Barrey and P. Galloux - 1997). 

The muscles involved in the successive sequences of the push-off have been clearly distinguished and their discriminated development can easily be achieved Like their human counterparts, equine athletes can be efficiently prepared for the effort. Hens, their talent may be enhanced by education rather than been used to compensate ineffective training approaches. Human athletes have long understood that natural reflexes were adapted to natural moves, rather they were hill adapted to the stylized version of the move demanded in the show ring. The concept of “practice makes perfect” vanished in favor of “perfect practice” where the focus is placed on the mastery of reflex combinations precisely adapted to the effort. Kinematics analysis and more recently the propensity to measure the forces developed and absorbed by the hind and front legs, permit to educate and orchestrate equine athletes’ physics as precisely as their human counterparts. Hitting the horses’ legs with a bamboo pole, which is a practice that remains in use behind the curtain, retrograde equine athletic training fifty years behind actual knowledge.

The practical application of actual knowledge allowed one to determine if the weaknesses observed during the take-off originate from muscle imbalance, poor coordination or insufficient supply of type II (fast twitch) muscle cells. The two first conditions may be modified with training, the distribution between fast and slow twitch muscle cells is genetic and cannot be modified with physical education. However, the knowledge of such distribution permits to tailor training approaches, riding style, and feeding to the horse’s individual needs. Recent studies have recognized two different types of fast twitch muscle cells, Type IIA and IIB, how they influences horses performances and their nutritional needs. Actual knowledge and the practical application of such knowledge situates horses education so far ahead of the gimmicks traditionally emphasized that one may wonder why some dressage trainers have dusted off the bamboo poles from the attic and bring them back, as a novelty, in the dressage ring.

Hitting the jumpers’ forelegs, the bamboo poles were addressing the wrong end of the problem. Touching the dressage athletes’ front limbs, the bamboo poles are handicapping even further the horses’ ability to perform piaff and passage. The nuances between “hitting” and “touching” are part of the cocktail party theories that embodies the art of “bamboo touching”. Location, duration, frequency and intensity of the touches are abundantly discussed keeping riders away from training techniques that would efficiently prepare the horses’ physic for the effort. 

The bamboo poles have been brought back from the attic in a desperate attempt to solve problems created by prior misconceptions. Our ancestors for whom kinematics analysis were limited to the capacities of the naked eye, were under the impression that horses were engaging their hind legs deeper under during piaff and passage Based on such impression they advise stimulating engagement and propulsive activity of the hind legs through touches of a dressage whip. The optical illusion was reinforced by the belief that the hind legs were exerting a propulsive force during the whole support phase. (The support phase, also referred to as stance phase, defines the sequence of the stride where the hoof is on ground contact). In respect of such belief, the longer the hind hoof remains under the horse’s body the greater the hind limb ability to carry the horses body upward. High-speed videos, platform measurements and accelerometers revealed a very different picture. In reality during piaff, the hind hoof alights and remains under the vertical of the croup during the whole support phase. Increasing the propulsive activity of the hind limb, the dressage whip is stimulating greater upward lift of the croup which in turns shifts the weight over the forelegs (Fig. 3). “If the pelvis is raised, horizontal forces are diminished but gravitational forces are doubly increased since raising the pelvis increases weight exerted at the anterior end and the pushing force is added to the gravitational forces at the anterior end.” (Richard Tucker – 1964)

Horses tempt to deal with the loading of their anterior end at the best of their imagination. Many increase the breaking action of the front legs dissociating the diagonal motion of the limbs as soon as the second or third step. Their performance became a walking piaff where each leg is moving independently. Some find creative compromises.  On one video document recorded for kinematics analysis by Nancy Deuel Toby Ph.D. along the dressage ring of the Atlanta Olympics, one horse placed the right front leg in front off him and the left front leg back under his belly. While raising the croup in rhythm with the extension of the hind legs, the horse moves his chest back and for from one leg to the other. Most horses shift the forelegs backward underneath their body balancing themselves over the front legs an bouncing their croup from one hind leg to the other. The posture was described in the early German literature as “a mountain goat standing on the tip of a mountain pick”. (Gustave Steinbrecht – 1886)

Rather than thinking the athletic performance through and concentrate the horses’ education on the coordination of muscle activities relative to the effort, training techniques turned to another gimmick, the bamboo poles, handicapping even further the horses’ ability to perform.

For a large part, the amplitude of the forelegs’ protraction is the product of the elastic strain energy created during the support phase. (The term “protraction” describes the sequence where the limb swings forward above the ground from  push-off to alighting). In a study titled: “A catapult mechanism for rapid limb protraction,” Wilson and al. linked thoracic limb protraction to a catapult mechanism, “in which energy is stored relatively slowly in elastic tissues during limb loading but is released quickly at toe-off, protracting the limb”. (AM Wilson, JC Watson, GA Lichtwark - 2003) In forward motion, thoracic limb protraction combines elevation and forward movement. During piaff, forelimb protraction is essentially an upward motion. When excessive weight is loading the front legs, the catapult mechanism is unable to lift the front legs and the amplitude of the protraction is poor. It is the defect than “bamboo touching” tempts to correct stimulating a mechanical elevation of the limbs. Doing so the bamboo pole handicap even further the horses’ ability to perform altering the “diagonalization’ of the rear and front legs and disturbing the dynamic cycle between hoof impact, slide and resonance. (The “slide”, is a shifting motion of the foot digging into the sand that lasts 20-30 ms after impact.)

The horse is one of the rare animals that considering the body mass can move quite fast and for a relatively long period of time. To achieve this survival necessity, nature has developed a sophisticated system of energy cost effective mechanisms that involves vibrations, shortening and elongation of the tendons rather than shortening and elongation of the muscles. “Foot impact excites the equine limb to vibrate in a cranio-caudal direction at a frequency of 30-40Hz. The vibrations are similar on different surfaces (tarmac 35.9 Hz: concrete 35.8Hz; rubber matting 34.9Hz), and correspond to a muscle-tendon change of about 2mm (from joint angle changes) and an energy of 4-8J. The vibrations are damped within 100ms on hard surfaces and more quickly on soft surfaces.” (Alan M. Wilson, M. Polly McGuigan, Anne Sue & Anton J. van den Bogert - 2001) Humans body, as well as all animals storing elastic energy in their tendon, uses the mechanism. Lifting the knees higher in response to the bamboo’s hit, horses increase the duration of the swing phase and shorten in proportion the duration of the stance phase. Doing so, they reduce the time where the energy that will stimulate the following swing phase is stored in the limbs’ elastic tissues.

Horses’ locomotion is based on a precise interaction between stance and swing phase. Idealizations of the gaits such as piaff and passage are in the spirit of the equestrian tradition the results of subtle orchestrations of the horses’ physic that magnify in turn the dynamics involved and consequently, amplitude and elevation of the limbs. Piaff and passage are the most difficult movements at the trot because they require the most precise body orchestration. Such mastery is the purpose of the horses’ physical education. Our ancestors activated the hind legs with a dressage whip because the knowledge available at their time let them believe that the stimulus was enhancing the horses’ abilities to perform. Duplicate their teaching in its original form is not respecting the equestrian tradition. Such conservancy falls into the job description of the horses’ museum conservator. The greatest lesson of the equestrian tradition is respect for the horse, which in the context of athletic performances commences with the ability to prepare efficiently the athlete’s physic for the effort.

“Respect for tradition”, wrote Colonel Danloux, should not prevent the love of progress”.  Progress is knowledge and in respect of the actual knowledge of the horse’s biokinematics, piaff and passage can be educate efficiently. During passage and even more during piaff, the hind legs decrease their propulsive activity and increase their breaking action: “The high collection of the passage transforms the forward propulsion into the upward propulsion. The forelimbs have a larger propulsive activity than the hindlimbs, which have a breaking activity.” (E. Barrey DVM,  S. Biau Ph.D. – 2002). Neither the whip, nor the bamboo and even half-halt will ever teach a horse to decrease the propulsive effort and increase the breaking activity of the rear legs.

Breaking and pushing phases are natural components of the hind and front limbs cycles. Under normal circumstances, the hind legs break from impact to approximately 45% of the support phase. The forelegs break from ground contact to 40% of the stance phase. The beautiful work of Eadweard Muybridge (1830 – 1904) permit to visualize the breaking and pushing phase of the hind legs in their real context. During the first half of the stance phase, (the breaking phase), the joints fold under the load and the muscles resist the folding accumulating an energy that will be quickly release assisting the pushing phase, (the second half),. During the breaking phase the hoof exerts on the ground a force in the direction of the motion. During the pushing phase, the hoof exerts on the ground a force opposed to the movement. Breaking and pushing actions are influenced by the biomechanical properties of the horse’s thoracolumbar spine, which convert the thrust generated by the hind legs into horizontal and vertical forces.

Those are the components of a better way that will be the subject of our second discussion,

“Most men”, wrote Bertrand Russell, “would rather die than think. Many do”. As a generic term, the word ‘men’ could be extended to riders who rather not think the performance through, stalling the training of the equine athlete at the level of superficial analysis and empty language. The knowledge that has the potential to rises both horses and riders’ talent to great performances is available. The practical application of this knowledge is actual reality. Some rather resist evolution dusting off the bamboo poles from the attic. Their fate is dictated by the natural law of evolution. Beauty and keenness for the horse will soon reenter the dressage ring. Gifted horses will be efficiently prepared for the effort. Their talent and the skill of their riders will be acerbate by efficient technique rather than been used to compensate ineffective approaches. 

.                                                                               Jean Luc Cornille