Impulsion

Impulsion is the movement of a horse when it is going forward with controlled power. Related to the concept of collection, impulsion helps a horse effectively use the power in its hindquarters. To achieve impulsion, a horse is not using speed, but muscular control; the horse exhibits a relaxed spinal column, which allows its hindquarters to come well under its body and "engage" so that they can be used in the most effective manner to move the horse forward at any speed.

The concept and term was first written about by practitioners of dressage, but an ability to move with impulsion is a desired goal in most other equestrian disciplines. Impulsion occurs when a horse is under human control and is one of the desired goals in horse training, but it may sometimes be exhibited by a horse in a free and natural state. Impulsion allows any horse gait to be more elastic and light, and also provides the animal with the power needed to perform complex movements, including the piaffe and the airs above the ground. Within the dressage world, there is an unresolved debate whether impulsion can only occur in gaits which have a period of suspension, the trot and canter, or if it occurs at any gait, including the walk and the ambling gaits.

There are competing definitions of impulsion. The 2007 USDF rule book defines it as "...Thrust. Releasing of the energy stored by engagement. The energy is transmitted through a back that is free from negative tension and is manifested in the horse's elastic, whole-body movement. The classical dressage trainer Nuno Oliveira described impulsion as, "...a mental and physical state of the horse to obey the rider's demands as fast as possible, to move forward, and to maintain his forward impulsion without support from the aids..." and ""Impulsion means to maintain the energy within the cadence." Another definition is that "[a] horse is said to have impulsion when the energy created by the hind legs is being transmitted into the gait and into every aspect of the forward movement. A horse can be said to be working with impulsion when it pushes off energetically from the ground and swings its feet well forward." The USEF states, "Impulsion is the term used to describe the transmission of an eager and energetic, yet controlled propulsive energy generated from the hindquarters into the athletic movement of the horse. Its ultimate expression can be shown only through the horse’s soft and swinging back to be guided by a gentle contact with the rider’s hand."

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