In American football

American football

American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football. The ball can be advanced by...

, clock management is an important aspect of game strategy. The team who holds the lead in the game will want to use as much time as possible, while the team that is trailing will want to conserve time so that there is enough to try to score.

Upon kickoff the clock is started when a member of the receiving team touches the ball, and it is stopped when that player is tackled or goes out of bounds. The clock is then restarted when the offense snaps the ball for their first play and continues to run unless one the following occurs:

• A player carrying the ball goes out of bounds (within the last five minutes of a half).
• A forward pass is ruled incomplete. (Included in this is the rule whereby the quarterback can "spike" the ball near himself without being called for intentional grounding
  Intentional grounding
  In gridiron football, intentional grounding is when a quarterback throws an incomplete pass toward an area of the field where there is clearly no eligible receiver. The penalty usually results in the loss of a down as well as 10 yards...
  
  . The team loses no yardage by doing so, only the down, and gains the benefit of the stopped clock.)
• Either team calls for a "Time Out" (see below) or an official calls for a time out, perhaps because a player is injured or there is a penalty on the play. Officials will restart the clock after an official time out, but not a team time out, has concluded unless another of the conditions applies.
• A player from either team scores a touchdown
  Touchdown
  A touchdown is a means of scoring in American and Canadian football. Whether running, passing, returning a kickoff or punt, or recovering a turnover, a team scores a touchdown by advancing the ball into the opponent's end zone.-Description:...
  
  , or a player from the offensive team kicks a field goal
  Field goal (football)
  A field goal in American football and Canadian football is a goal that may be scored during general play . Field goals may be scored by a placekick or the now practically extinct drop kick.The drop kick fell out of favor in 1934 when the shape of the ball was changed...
  
  .
• Possession of the football is transferred between teams for any reason.
• In college football
  College football
  College football refers to American football played by teams of student athletes fielded by American universities, colleges, and military academies, or Canadian football played by teams of student athletes fielded by Canadian universities...
  
  , the clock is briefly stopped when a team earns a first down
  Down (football)
  A down is a period in which a play transpires in American and Canadian football.-Description:A down begins with a snap or free kick , and ends when the ball or the player in possession of it is declared down by an official, a team scores, or the ball or player in possession of it leaves the field...
  
   to allow the chain crew
  Chain crew
  In American football, the chain crew are assistants to the referee who handle the first down measuring chain and the down indicator box...
  
   to reposition themselves. The NFL has no such stoppage.
• The clock runs out. If this happens during a play, the current play continues until the ball is dead.

Each team is given three "time outs" per half which they can use to stop the clock from running after a play.

A Strategy For Managing Game Pace

The players on the field can influence the pace of the game greatly simply by the way they conduct their activities. An offense can go to a no-huddle offense where they line up as soon as the ball is placed by the official, and either run a pre-determined play or audibly call the next play at the line of scrimmage. This is a hurry-up offense.

Conversely a team can slow the pace of a game by taking the maximum amount of time allotted between plays. There is a play clock

Play clock

A play clock is a timer designed to increase the pace in American football and Canadian football, similar to what a shot clock does in basketball...

 which allows the offense 40 seconds from the time the ball is placed until they must snap their next play. A team wishing to use as much clock as possible would wait to snap the ball until the last possible second, assuming the game clock was still running, in order to use at least 40 seconds off the clock every play they run.

Some teams employ a system to tell their players what pace to play at—for example: Slow, Normal, Fast.

Slow

Used when you want to use as much clock as possible this tells your players to play in a manner that will maximize your clock usage. That means that ball-carriers must stay in-bounds. Quarterbacks must minimize incomplete passes, even to the extent that they look for opportunities to run with the ball rather than throw it away if no open receiver presents. Also the offense will huddle after each play and the quarterback will wait to snap the ball until as much of the play clock as possible has been used. This is commonly associated with the Smashmouth offensive philosophy, which aims to keep the opposing defense on the field as long as possible to tire them out.

Normal

Self-explanatory; this tells the offense to run and call plays as they normally would without concern for the clock.

Fast

Opposite of slow, of course. Ball-carriers should look for opportunities to get out of bounds when they have gained as many yards as possible. Quarterbacks should speed up their decision-making and not hesitate to throw the ball away rather than take a sack or a short run. The offense may not huddle or will hustle in and out of the huddle quickly and the ball will be snapped quickly.