James Fillis published his Principes de Dressage et d'Equitation in 1890. He was a student of François Caron, who was a direct pupil of Baucher. He was the most systematic thinker about equine balance who ever put pen to paper. And the thing he was most systematic about was not movement, not collection, not flexions — it was physics.
The Weight Distribution Problem
The horse carries approximately 60 per cent of its total body weight on its forehand at rest. This is anatomy, not training assessment. The heavy head and neck, the thoracic mass, the shoulder — the horse is structurally front-heavy. The entire purpose of training, in Fillis's framework, is to shift this distribution rearward. This is a physics problem, not an aesthetic one. And it has a physics answer.
The Lever Arm
The horse's head and neck assembly accounts for roughly 10 per cent of total body weight — 50 to 80 kilograms in a typical warmblood. The neck is a long lever arm, cantilevered forward from the shoulder. When the horse raises and rounds its neck — bringing the poll up, shortening the upper line, bringing the nose toward the vertical — the centre of mass of the head-neck assembly shifts backward. The lever arm shortens. The rotational moment pulling the forehand down decreases. Weight is redistributed rearward.
When the head goes behind the vertical, the centre of mass shifts forward. The lever arm lengthens. The mechanical load on the forehand increases.
Fillis's Own Words
"The moment the axis of the head comes behind the perpendicular, the action of the curb is false, because it works from below upwards. Then the horse begins to draw his chin into his breast." — James Fillis, Breaking and Riding (1902), p.55
This is not a stylistic observation. It is a mechanical statement. When the horse's nose goes behind the vertical, the curb bit reverses its action. It works from below upward instead of downward on the bars. Rather than lifting the front end it tucks the chin further toward the chest. The instrument of collection becomes an instrument of further compression.
Fillis then describes Baucher's incorrect flexion — head low, behind the perpendicular, all weight on the shoulders — and states: the horse has all his weight on his shoulders, and the action of the curb is consequently false.
The FEI's Own Internal Contradiction
The FEI rules require the horse to go with its nose slightly in front of the vertical at all times. The same rules describe the Give and Retake of the Reins — the movement designed to test self-carriage — as one where the horse's nose may come slightly in front of the vertical.
If the horse was already in front of the vertical, there is nowhere for it to come to. This movement only makes sense if the horse was, in normal work, behind the vertical. The rules simultaneously forbid behind the vertical and describe a scoring structure that only makes sense if behind the vertical is the norm. This contradiction has survived multiple revision cycles unaddressed.
Three Independent Lines of Evidence
Classical prescription, Newtonian mechanics, and modern physiology all converge on the same conclusion: the nose must be at or in front of the vertical for genuine collection to be mechanically possible.
The sport has constructed a judging culture that rewards the one head position all three lines of evidence condemn. This is not an oversight. It is what the incentive structure, operating over forty years, selected for.