Michele and I had the privilege of visiting the ranch of Gary Long 'Long Ranch' in Naches recently.  Prior to the visit, I never really thought about the need to 'train' a Bull to buck... I though that's just what they do.  But training is all part of the game!  Check out the video.  They put these weighted devices on the back of the Bull's... the devices have a remote detach to come undone after 8 seconds.  It's pretty sweet to watch.