First how did the rider score? It really does help understanding what happened and the commentary.
**Slow doesn’t necessarily mean it wasn’t active - Maybe they meant the horse was a bit earthbound or the movement felt labored? A rhythm problem is much more costly.
That is why it is important to refer to the rules, the test sheet and the judging guidelines - it really is the best way to learn about dressage. And judges also have their handbook - which is not available for free online. (65CHF)
Test sheet for Piaffe score : Regularity, taking weight, self-carriage, activity, elasticity of back and steps. (Specific number of diagonal steps - When asked)
FEI Dressage rules
ARTICLE 415 THE PIAFFE
- 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. Each diagonal pair of legs is raised and returned to the ground alternately, with spring and an even cadence. Regularity
1.1. In principle, the height of the toe of the raised forefoot should be level with the middle of the cannon bone of the other supporting foreleg. The toe of the raised hind foot should reach just above the fetlock joint of the other supporting hind leg.
1.2. The neck should be raised and gracefully arched, with the poll as the highest point. The Horse should remain “on the bit” with a supple poll, maintaining soft contact. The body of the Horse should move in a supple, cadenced and harmonious movement.
1.3. Piaffe must always be animated by a lively impulsion and characterised by perfect balance. While giving the impression of remaining in place, there may be a visible inclination to advance, this being displayed by the Horse’s eager acceptance to move forward as soon as it is asked.
1.4. Moving even slightly backwards, irregular or jerky steps with the hind or front legs, no clear diagonal steps, crossing either the fore or hind legs, or swinging either the forehand or the hindquarters from one (1) side to the other, getting wide behind or in front, moving too much forward or double-beat rhythm are all serious faults.
The aim of piaffe is to demonstrate the highest degree of collection while giving the impression of remaining in place.
Guidelines for evaluating the piaffe, transitions and the walk : (GP)
Other faults are as follows:
Guidelines for piaffe at Inter A et B :
« We have to remain true to the principle that it must be possible to award a the maximum score,‘10’, for every exercise that is asked for in the tests, provided that the quality can be regarded as ‘excellent’.
Therefore, if we see perfectly regular, highly expressive piaffe steps that are ‘allowed to travel forwards 2 meters’, as in the A and B tests, we should be prepared to award the maximum score.
If however, the piaffe is shown ‘more or less in place’ as in the Grand Prix, and is performed in an ‘excellent’ way, we should still be prepared to award the maximum score, as the guidelines for the A and B tests only state that it is ‘allowed’ to advance for up to two metres. Nowhere is it stated that the piaffe ‘must’ advance two metres. »
Next are Guidelines for marking the fundamental dressage movements :
https://inside.fei.org/system/files/Guidelines%20for%20Marking%20of%20Fundamental%20Mistakes%20in%20Dressage%20Movements.pdf
Too much forward
Advancing for more than 4-5m ; showing half steps = Below 5; lower if travelling even more
Travelling approximately 3 ” 4 m = Below 6
Travelling approximately 2 m = Deduction of 1 ” 2 p.