Stanley Kubrick was never one for realistic films about ordinary people; the nearest he came to a straightforward drama was probably the heist movie, The Killing. This shying away from realism seems to show itself in his very first film, this short documentary about the boxer, Walter Cartier, preparing for and engaging in a fight. Any boxer is a special person, but some directors might have portrayed Cartier as a regular guy with a particular skill; but from the start Kubrick stresses Cartier's unusualness by showing waking up beside, and going around town with, his identical twin brother, giving a surreal aspect to the film.
The way Cartier psychs himself up for the fight in his dressing room, turning himself into a fighting machine, also seems to fit in with Kubrick's later interest in making films about people under stress (eg Full Metal Jacket) or in an abnormal state (eg The Shining and Clockwork Orange). It is also intriguing to wonder whether the director's fondness for voiceover narrative in his feature films stems from this and his other early documentaries. Oh, by the way, it's quite a good documentary about a fighter who, in fact, never became champ, and went into TV and films.