In film making its a basic guideline regarding the on screen spatial relationship between a character or object within a scene. The rule states that the camera should remain at the same side of a imaganary line. The line is drawn, perpendicular to the camera's viewpoint in the establishing shot of the scene enforcing the continuity of the film. Such rules should never be broken however it is permitted for effect. Breaking the rule in scenes that containing a chase, conversation or aspect of sport results in such problems such as confusing the audience, the audience loses focus and they become disorientated subsequently missing vital parts of the film.
Match On Action
Match on action is a editing technique used for continuity purposes. Match on action is where one shot cuts to another shot portraying the action or subject in the first shot. This creates the impression of a sense of continuity. The action that you see cutting through is called a visual bridge drawing the viewers attention away from slight cutting or continuity issues. This is not a graphic match or match cut but portray's a continuous sense of the same action rather than matching to seperate things.
A series of shots that views the action from the opposite side of the previous when two characters are in dialouge to give the impression that they are both looking at each other.