Originally Posted by FutureVetGirl
she could find a good enough rider who can ride the horse, and when the horse acts up, make him stop immidiately. Then canter again, and when the horse bucks, stop once more. Like, a complete halt, pretty much right as he's bucking. Don't wait until he finishes. Pretty soon, he'll learn that he can't do anything if he bucks.
Actually that is the wrong thing. It teaches a horse that bucking means he gets to stop working.
The best way is to either work his energy off before riding by lunging him or being ready to pull his head up and move him forward when you start out on a canter.
A lot of horses do that. On a cool or windy day my guy will do that if I ask for a canter before he is warmed up. It's a good thing to warm him up anyway before cantering off to get those muscles in shape. There are some Western horses (English too) that are considered "cold backed" meaning that they may be a little rodeo before warming up.
Lunging him is not to wear him out but take the edge off.