6 years ago, a woman I boarded with a woman who bought a TB that had many
behavioral problems, including pulling back when tied. After many failed
sessions with various local trainers, she sent the horse to a QH training
facility east of Atlanta. This place had a couple of mules that were used to
"train" horses. The TB was tied to one of these special mules,
and after a few days the mule would be dragging the horse around at
will...sometimes the horse would be dragged lying flat out on the ground. After
a couple of weeks being tied to the mule, the TB became very
docile(obviously!!). The owner of the horse was OK with this method and took the
horse back for "Tune-up" sessions every 6 months or so. By the way, I did
not approve of this method.