Running out the clock
In American football, each quarter of a game is measured with a 15-minute game clock, or 12-minute clock in many high school football codes and the German Football League. A team in possession of the lead and the ball will attempt to use up as much of the game clock as possible in order to bring the game to an end more quickly, thus denying the opposition another chance on offense.
Arena football
The clock stops for out-of-bounds plays, incomplete passes, or sacks only in the last minute of each half or overtime (there is only a one-minute warning, as opposed to the two-minute warning in the NFL and the three-minute warning in the CFL) or because of penalties, injuries or timeouts. The clock also stops for any change in possession, until the ball is marked ready for play; for example, aside from in a half's final minute, time continues to run down after a touchdown, but stops after an extra point or two-point conversion attempt. If a quarter ends as a touchdown is scored, an untimed conversion attempt takes place. The play clock is 32 seconds, starting at the end of the previous play. In all arenas, the final minute of the period is measured in tenths of a second.