Upper body control, strong legs, and great balance is essential when riding bulls. Failure to do this could cause him to lose balance or to be tossed forward when the bull bucks. The other half is based on the animal. A rider may only make up to 50 points for their efforts. The other 50 points must come on how well the bull performs.
Judges watch for good body position as well as control.
Other factors that reflect on the score is use of the free arm and spurring action. Although not required, spurring will only add points to your ride. They will also watch the pattern of the bull and how hard it was to make the ride. A re-ride may be awarded for various reasons. The most common one is that the bull failed to perform well.