Well, I am going to make a real no brainer statement coming from a newbe.
All these years I have been under the impression, when a horse is putting
out a big trot (extended) it is the natural position for the horses to
extend the neck in a comfortable, go forward position.
A horse that is held back (riding on the rains to slow the trot) or
collected so to say, would always be inclined to stretch and relax.
(unless the horse was trotting as a posturing movement in the field etc..)
Sigrid
The Space Cadet