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.
Overtime (sports)
High school rules vary depending on the state and conference, but most will have a sudden-death overtime procedure wherein the game ends upon scoring a golden goal, although in some instances the overtime will go until completion with the team in the lead after time expires (i.e., silver goal rules) declared the winner. The overtime period length may vary, but it is commonly 10 minutes long. Depending on the state, if the game is still tied at the end of the first overtime:The NFL introduced overtime for any divisional tiebreak games beginning in 1940, and for championship games beginning in 1946. The first postseason game to be played under these rules was the 1958 NFL Championship Game between the Baltimore Colts and New York Giants (the so-called "Greatest Game Ever Played").