The FEI dressage rule definition of the piaffe is: “Piaffe is a highly collected, cadenced, elevated diagonal movement, giving the impression of remaining in place. The horse’s back is supple and elastic. The hindquarters are lowered; the haunches with active hocks are well engaged, giving great freedom, lightness and mobility to the shoulders and forehand.”
The piaffe is basically trot on the spot. It is one of the movements introduced at Medium tour where it is allowed to move forward; and then in Grand Prix it is “in place” (on the spot), which takes a huge degree of finesse, energy and balance. It carries a lot of marks at the Grand Prix level, and it is also a combination movement with passage where the transitions in and out of it are marked separately.
In the Grand Prix Special, it is also done from the walk to piaffe, and so it is that the piaffe is of the utmost importance to train well as it has a huge bearing on the marks at this level. Not only for the marks, but for building balance and strength, and it is said to help with activity and the canter. If trained incorrectly it can have a detrimental effect on the quality of the walk.
It is also a movement that many riders find difficult and, through too much pressure, create huge tension and resistances in a movement that is simply an excited horse trotting on the spot. It is really a very active and energetic jog and most horses don’t find that hard and the excitable ones find it easy. It is just a matter of channelling the horse’s energy into understanding the aids and the concept.
There is no real time frame about when to start training the piaffe. It is an exercise that some horses find easy as anything and others find it very complicated. A horse that has a tendency to want to jog instead of walk is obviously an easy candidate for the piaffe. There is no definite time or age when to start the piaffe, and really, the training for the piaffe starts with every transition from trot to walk and walk to trot, as it’s about being on the bit, through and over the back and learning to come back with active shortened steps. So, when you think of it like this and say as you collect the trot more and more, “I am not going to let you walk yet”. Just stay active and with super short steps, then ride forward again or keep short steps and melt into collected walk.