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.
One-minute warning
At the one-minute mark of any given half or overtime, the referee announces: "One Minute Timing Rule in effect". During the final minute of play, the game clock changes from a continuously running clock (except for scores and time-outs) to a clock that mirrors NCAA rules (stopping on first downs, out of bounds, incompletions, and so on.) Since 2018 teams can do "sandbagging" via the quarterback kneel, a tactic common in the NCAA and NFL to run out the clock with minimum risk. It also rewards defensive play, as a tackle for loss automatically stops the clock. Any player injured during this time and that team uses a timeout.
In the former X-League, after the one-minute warning or in overtime, the "X-Bonus" rule came into play. All scoring during the final minute of play was worth double what it is normally worth, and a special black football was used.