What types of combat do fans of Heroes enjoy?

Sambo. There's no violence in it. Unless you're in training, not in a competition, or in an alley. And what kind of violence are we even talking about, if it's self-defense without weapons? Unless two sambo practitioners meet...

It depends on what kind of sambo you're talking about. In the combat version, it's rare for things to end without dislocated joints and/or torn ligaments. I used to practice hand-to-hand combat and dealt with such tough guys; it was difficult (probably the most uncomfortable opponent out of all styles).