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.
Australian rules football
A game consists of four quarters and a timekeeper officiates their duration. At the professional level, each quarter consists of 20 minutes of play, with the clock being stopped for instances such as scores, the ball going out of bounds or at the umpire's discretion, e.g. for serious injury. Lower grades of competition might employ shorter quarters of play. The umpire signals "time-off" to stop the clock for various reasons, such as the player in possession being tackled into stagnant play. Time resumes when the umpire signals "time-on" or when the ball is brought into play. Stoppages cause quarters to extend approximately 5–10 minutes beyond the 20 minutes of play. 6 minutes of rest is allowed before the second and fourth quarters, and 20 minutes of rest is allowed at "half-time".