samsara
Posted : 1/28/2010 8:43:24 PM
This is a really bad and
very dangerous habit.
What kind of halter do you use? A rope halter could help deter this a little, especially the kind with the knots over the poll.
You could try a blocker tie-ring they allow you to tie the horse but if he should pull back it releases a bit of slack in the lead rope
http://horseloversoutlet.com/blocker_tie_rings.html When you tie a horse to a solid object and he pulls back there is a lot of tension put on the halter and the rope, the horse feels trapped and then 
anics, pulls harder and something breaks. With the tie ring the horse pulls back, some slack is released in the line, horse doesn't feel trapped anymore, problem solved.
They're not a cure all and if this has developed into a legitimate habit and not a fear response to being tied then you'd better get yourself to a trainer who can help you.
Good luck!