Joe-Joe said, Pulling is not as effective as having the horse bend, stretch and flex on his own (treats help a lot with this). A horse cannot collect himself without muscle, and I, for one, do not like to see the head behind the vertical. It constricts the throat and accomplishes nothing. The horse should reach for the bit, not be pulled back to it.
Just my opinions, based on 57 years of experience.
I am saying that, Your NOT pulling, you are massaging its neck around, treats do not help some horses (all horses are different). Personally, Years of experience means nothing if you have not learned the right stuff that ACTUALLY is effective. The horse should give to the bit, not make you work harder. Trust me, the things that I said before works. My horses have nice muscle tone. There is many things out there that don’t work it just distracts the horse from working out the problem and the rider is just trying to make the horse happy or there is different ways to do it but it is not the right way (or not the natural way) of building muscle. The stuff I said before does work, my horse built muscle in just a month or so of working, but it does depend on the acceleration of the horse, rider, or both. Cause some people DO NOT know how to ride even if they have been riding for a long time.