To ride from "front to back" means that the rider is using their hands to artificially shape the horse's head and neck, rather than letting the head and neck position change naturally as the overall carriage of the horse improves with training (ie collection.)
For the horse, the learning happens on the release of the aid. That means if you don't release the aid, the horse will not learn.
"Don't take the tempo down without revving the engine." ~ Chris Bartle
I don't even think about aiming a young or green horse at a jump until I have them 100% in front of my leg on the flat. If you do, and the horse thinks about stopping, you will have no recourse, and will end up teaching him that
From Facebook fan Joan Dunlap ~ "Fix your position first... then the horse will adjust theirs."