Ok, here is what I remember of the movie. In the movie, it is futuristic. A human is a fighter in a world that has various creatures that fight as well. He has to fight various ones and at the end has to fight this one that looks half man half bull. I am not really sure what the name of the movie is, but would love to know.

The movie you are looking for is Arena (http://www.imdb.com/title/tt0101366/) from 1989, starring Paul Satterfield, currently appearing on the soap opera One Life to Live, Claudia Christian of Babylon 5 fame, and Marc Alaimo and Armin Shimerman from Deep Space Nine. It was written by Danny Bilson, father of actress Rachel Bilson.