premise: Action films are a subgenre of martial arts films.
hypothesis: Kung fu film is a subgenre of martial arts films and Hong Kong action cinema set in the contemporary period and featuring realistic martial arts . Martial arts film . A subgenre of the action film , martial arts films contain numerous martial arts fights between characters . Martial arts films commonly include other types of action , such as hand-to-hand combats , stuntwork , chases , and gunfights .