In football, a running clock refers to a clock that does not stop during the game, except for specific situations. The use of a running clock is often employed in situations where one team has a significant lead over the other, and the game is no longer competitive. The rules for a running clock vary depending on the level of play and the specific league or organization. Here are some examples:

• NCAA Football: The NCAA Football Rules Committee allows the remaining quarters to be shortened to 12 minutes each if the coaches and the referee agree. However, a running clock is not allowed, and normal clock rules apply for the entire game.

• High School Football: In high school, each quarter is 12 minutes long, and the clock doesnt run all of the time. However, some states have a mercy rule that may involve a "continuous clock" once a team has a certain lead during the second half.

• NFHS Football: The National Federation of State High School Associations allows a running clock to be used for varsity regular-season games, playoff games, and state championship games for six, eight, and eleven-man football whenever a 35-point score differential is reached after the first half of play. The clock will run continuously except for specific situations.

In general, a running clock is used to shorten the game and bring it to an end more quickly when one team has a significant lead. The clock will continue to run during most plays, and it will only stop for specific situations, such as timeouts, injuries, or penalty enforcement.