American football rules - AbsoluteAstronomy.com

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...

consists of a series of downs, individual plays of short duration, outside of which the ball is dead or not in play. These can be plays from scrimmage—passes, runs, punts, or field goal attempts—or free kicks such as kickoffs. Substitutions can be made between downs, which allows for a great deal of specialization as coach

Coach (sport)

In sports, a coach is an individual involved in the direction, instruction and training of the operations of a sports team or of individual sportspeople.-Staff:...

es choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.

Objective of the game

The objective of the game is to score more points than the opponent during the allotted time. Points are scored as long as one of the teams controls the ball. The team with the ball (the offense) has 4 tries (downs) to advance at least 10 yards, and can score points once they reach or near the opposite end of the field, called the end zone
End zone
In gridiron-based codes of football, the end zone refers to the scoring area on the field. It is the area between the end line and goal line bounded by the sidelines. There are two end zones, each being on an opposite side of the field...

. If the offense does not advance at least 10 yards during their 4 downs, the team without the ball (the defense) regains control of the ball (called turnover on downs
Turnover on downs
In American football, a turnover on downs occurs when a team fails to convert a fourth down into a first down by gaining the required yardage.A team has four chances to gain ten yards or to score. Any ground gained during one down short of these ten yards is kept for the next chance...

).

On offense, points are scored by advancing the ball into the opponent's end zone for 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:...

(worth six points), or by kicking the ball from the playing field through the raised vertical posts (the goal posts) in the back of that end zone for a field goal
Field goal
A field goal is a general term used in some sports wherein a goal may be scored either during general play or via some sort of free shot...

(worth three points). After scoring a touchdown, the offense is given one additional play from the 2 yard line (3 yard line in amateur football) to attempt to score. These attempts are termed point after touchdown (PAT) and are used to score 1 or 2 points as follows:

The offense may attempt a field goal kick which is worth 1 point.
The offense may attempt to re-advance the ball into the opponent's end zone for a two-point conversion worth 2 points.

While on defense, the defense attempts to prevent the offense from advancing the ball and scoring. If an offensive player loses the ball during play (a fumble) or the ball is caught by a defensive player while still in the air (an interception), the defense may attempt to run into the offense's end zone for a touchdown. The defense may also score points by tackling the ball carrier in the offense's own end zone, called a safety (worth two points).

Time of play

Collegiate and professional football games are 60 minutes long, divided into four quarters of 15 minutes each. In high school football, 12 minute quarters are usually played. The clock is stopped frequently, however, so that a typical college or professional game can exceed three hours in duration. The referee controls the game clock and stops the clock after any incomplete pass or any play that ends out of bounds. In addition, each team is allowed 3 timeouts in each half that they may use at their own discretion.

The clock may also be stopped for an officials' time-out, after which, if the clock was running, it is restarted. For example: if there is a question as to whether or not a team has moved the ball far enough for a first down, the officials may use a measuring device (the chains) to determine the distance. While this measurement is taking place, the officials will signal for a stoppage of the clock. Once the measurement is finished and the ball is placed at the proper location (spotted), the referee will then signal for the clock to restart. Additional situations where officials may take a time-out are to administer a penalty or for an injured player to be removed from the field.

In addition to the game clock, a separate play clock is also used. This counts down the time the offense has to start the next play before it is assessed a penalty for delay of game (see below). This clock is typically 25 seconds from when the referee marks the ball ready for play. The NFL and NCAA use a 40-second play clock that starts immediately after the previous play ends, though for certain delays, such as penalty enforcement, the offense has 25 seconds from when the ball is marked ready. The purpose of the play clock is to ensure that the game progresses at a consistent pace, preventing unnecessary delays.

Officials also call for media time-outs, which allow time for television and radio advertising. They also stop the clock after a change of possession of the ball from one team to the other. Successful PATs (Point(s) After Touchdown), a field goal try, or a kickoff may also warrant stopping the clock. If an instant replay challenge is called during the game, the referees signal for a media time out. The referee signals these media time-outs by first using the time out signal, then extending both arms in a horizontal position.

Separating the first and second halves is halftime. Teams change ends of the field at the end of the first quarter and the end of the third quarter. In the NFL, an automatic timeout is called by the officials when there are two minutes left in both the second and the fourth quarters; this is most commonly referred to as the two-minute warning. No such warning is normally given in amateur football, though if there is no visible stadium clock, the referee will give a two-minute warning (four minutes in high school).

Overtime

If a game is tied at the end of four quarters, overtime is played.

During the regular season in the NFL, one sudden-death overtime period is played (with each team receiving two time outs) wherein the first team to score is declared the winner. If neither team scores during the 15-minute overtime, the game officially ends in a tie. Overtime follows a three-minute intermission after the end of the regulation game. Prior to start of overtime, a coin flip is performed wherein the captain of the visiting team calls the toss. The team that wins the coin flip has the option to either receive the kickoff or choose the side of the field they wish to defend. Ties are rare in the NFL; the game between Philadelphia
Philadelphia Eagles
The Philadelphia Eagles are a professional American football team based in Philadelphia, Pennsylvania. They are members of the East Division of the National Football Conference in the National Football League...

and Cincinnati
Cincinnati Bengals
The Cincinnati Bengals are a professional football team based in Cincinnati, Ohio. They are members of the AFC's North Division in the National Football League . The Bengals began play in 1968 as an expansion team in the American Football League , and joined the NFL in 1970 in the AFL-NFL...

on November 16, 2008 ended in a tie, the first tie since 2002.

For NFL 2010 post-season games, a modified sudden-death system of determining the winner is used during overtime play. If the team (Team-A) that receives the opening kickoff in overtime scores a touchdown on their opening drive, then the game is over and they are the declared the winner. If, however, a touchdown is not scored on Team-A's opening drive, then the other team (B) is given an opportunity to possess the ball (for example, Team-A may opt to punt the ball away, or fail to make a first down on their fourth down attempt). Once the requirement for possession, or opportunity-to-possess, has been satisfied by both teams then normal sudden-death rules apply, meaning that the next team to score wins the game. Various events may occur that constitute opportunity-to-possess even though a team may not gain full possession of the ball in order to run a play. For example, a team that muffs a kickoff or punt return (i.e., drops the ball while attempting to catch it) which is then recovered by the kicking team, is considered to have had their opportunity-to-possess. If the recovering (kicking) team goes on to score, then the game is over. Similar to normal overtime, following a three-minute intermission after the end of the regulation game, a coin flip is performed wherein the captain of the visiting team calls the toss. However, in post-season overtime, multiple 15-minute overtime periods may be played until a winner is declared.

NFL Europa, a defunct league run by the NFL, used a 10-minute overtime period, with the constraint that each team must have the opportunity of possession; once both teams have had such an opportunity, the overtime proceeds in a manner similar to the NFL's. Thus, if Team A has the first possession of overtime and scores a touchdown and converts their kick (thus being 7 points ahead of Team B), Team A would then kick off to Team B (In the NFL, the game would have ended with the touchdown, without a conversion being attempted). Team B would have to match or exceed the 7 point difference within this ensuing possession; exceeding it would end the game immediately, while matching the difference would result in a kickoff to Team A. From this point, the overtime is sudden death. The new United Football League also uses this rule.

The defunct World Football League
World Football League
The World Football League was a short-lived gridiron football league that played in 1974 and part of 1975. Although the league's proclaimed ambition was to bring American football onto a worldwide stage, the farthest the WFL reached was placing a team – the Hawaiians – in Honolulu, Hawaii. The...

, in its first season of 1974, used an overtime system more analogous to the system long used in international soccer
Football (soccer)
Association football, more commonly known as football or soccer, is a sport played between two teams of eleven players with a spherical ball...

. The overtime consisted of one 15-minute period, which was played in its entirety and divided into two halves of 7½ minutes each, with each half starting with a kickoff by one of the teams. The league changed to the NFL's sudden-death format for its second and last season in 1975.

In college and high school football, an overtime procedure (the Kansas plan) ensures that each team has equal opportunity to score. In college, both teams are granted possession of the ball at their opponents' 25 yard-line in succession. A coin flip takes place, with the winning team having the option either 1) to declare that they will take the ball first or second, or 2) to decide on which end of the field the series will occur (both teams' series occur on the same end of the field). The losing team will have the first option in any subsequent even-numbered overtime. In the first overtime, the team with first series attempts to score either a touchdown or a field goal; their possession ends when either a touchdown or a field goal have been scored, they turn the ball over via a fumble or an interception, or they fail to gain a first down. After a touchdown, a team may attempt either an extra-point or a two-point conversion. However, if the team on defense during the first series recovers a fumble and returns it for a touchdown, or returns an interception for a touchdown, the defensive team wins the game. (This is the only way for a college overtime game to end without both teams having possession.) Otherwise, regardless of the outcome of the first team's series (be it touchdown, field goal, or turnover), the other team begins their series. If the score remains tied after both teams have completed a series, a second overtime begins. If the score remains tied after two overtimes, teams scoring touchdowns are required to attempt a two-point conversion from the third overtime on. Just as in regulation, if a defensive team recovers a fumble/returns an interception to the end zone during a two-point conversion attempt, they will receive two points.

In high school football in a majority of states, each team is granted possession of the ball at the 10-yard line, meaning that a team cannot make a first down without scoring except via a defensive penalty that carries an automatic first down (such as defensive pass interference
Pass interference
In American and Canadian gridiron football, pass interference is a penalty that occurs when a player interferes with an eligible receiver's ability to make a fair attempt to catch a forward pass. Pass interference may include tripping, pushing, pulling, or cutting in front of the receiver or...

or roughing the passer). As is the case with the college overtime rule, the team that wins the coin toss will have the choice as to whether to take the ball first or second, or decide at which end of the field the overtime will be played. The other major difference between overtime in college football and high school football is that in high school football, if the defense forces a turnover, they may not score. However, in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, the college overtime rule is used, as both the University Interscholastic League
University Interscholastic League
The University Interscholastic League is an organization that creates rules for and administers almost all athletic, music, and academic contests for public primary and secondary schools in the American state of Texas....

, which governs interscholastic activities for Texas public high schools, and the Texas Association of Private and Parochial Schools
Texas Association of Private and Parochial Schools
The Texas Association of Private and Parochial Schools, or TAPPS, is an organization headquartered in Salado, Texas which creates rules for, and sometimes administers, almost all athletic and academic contests for non-public high schools in the American state of Texas...

, the largest analogous body for Texas private high schools, play by NCAA football rules with a few modifications for the high school level.

The defunct XFL
XFL
The XFL was a professional American football league that played for one season in 2001. The league was founded by Vince McMahon, the Chairman of the Board of Directors of WWE...

used a modified Kansas Plan which, upon the first team scoring, required the opponent to score the same or greater amount of points in the same or fewer downs (i.e. if the first team scored a touchdown, and converted the one-point conversion in three downs, the opponent would have to match that touchdown and conversion in three downs as well). Each team started at the 20-yard line, but like high school, there were no opportunities for first downs. The league also banned field goals except for on a fourth down.

Coin toss

Three minutes before the start of the game, the referee meets with captains from both teams for a coin toss. The visiting team calls the toss. The winner of the toss may defer their choice to the start of the second half, or they may take first choice of:

Receiving the kickoff to start the game, or kicking off to start the game
Choosing an end of the field to defend in the first quarter (with the teams switching directions at the end of the first quarter and at the end of the third quarter)

The loser of the toss gets the remaining option.

At the start of the second half, the team that did not choose first (either because they deferred their choice or because they lost the toss) gets the first choice of options.

According to USA Today, in college games, the team that wins the toss defers their choice to the start of the second half over 90% of the time.

If a game goes to overtime, a coin toss is held before the start of overtime, but tosses are not held before the start of subsequent overtime periods. In college, for example, the loser of the toss to start overtime has first choice in the second overtime period. The choices available to the captains in overtime vary among the NFL, college, and various states' high school rules.

In high school, the coin toss may be held between the captains or coaches earlier before the start of the game. At three minutes before kickoff, the captains meet for a simulated coin toss, where the referee announces the results of the earlier toss.

Downed player

A player carrying the ball (the runner) is downed when any of the following occurs:

Any part of the runner other than his hands or feet touches the ground. Ankles and wrists count as downed. This may be as a result of:
- Contact by an opponent (called down by contact) where the opponent tackles the runner by pushing him, grasping him and pulling him to the ground, sliding into his legs, or touching him in any manner prior to any part of the runner other than his hands or feet touching the ground. Unlike the use of the word tackle in other sports, if the opposing player fails to down the ball carrier, it is merely an attempted tackle. If the ball carrier falls onto another player but he doesn't make contact with the ground, he can still get up and keep playing. The guy on the ground isn't considered part of the ground.
- Intentionally downing the ball: intentionally kneeling, verbally declaring "I'm down" (except in college), or similar actions. For example, to protect himself from violent hits by opponents attempting to tackle him, the quarterback may choose to slide to the ground feet-first. This slide is interpreted as intentionally downing the ball, and opponents may then be penalized for hitting him.
- In amateur football, a runner is downed when any part of his body other than his hands or feet touches the ground at any time (unless he is the holder for a place kick). In professional football, the runner is not down for such accidental contact; he must be down by contact with an opponent as described above.
The runner goes out of bounds: that is, any part of his body (including his hands or feet) touches the ground, or anything other than another player or an official, on or past a sideline or an endline. Note that the sideline itself is out of bounds, so that the runner is deemed out of bounds if he steps on or touches any part of it. Note also that a runner may carry the ball in such a manner that it is over the sideline, so long as the ball or runner does not touch anything out of bounds.
The runner's forward progress toward the opponents' goal line is stopped by contact with an opponent, with little chance to be resumed. The exact moment at which the player's forward progress stops is subject to the judgment of the officials. In particular, for the protection of the quarterback, he is considered down as soon as an official judges that he is in the grasp of an opponent behind the line of scrimmage, and the tackling defensive player(s) will be awarded with a sack
Quarterback sack
In American football and Canadian football, a sack occurs when the quarterback is tackled behind the line of scrimmage before he can throw a forward pass, or when the quarterback is tackled behind the line of scrimmage in the "pocket" and the intent of what he was going to do is unclear...

. If he is driven backward by the opponent, the ball will be spotted where his forward progress was stopped.

Scrimmage downs

The majority of a football game takes place on plays, or downs, that begin at the line of scrimmage. The officials spot the ball (place it in a designated spot on the field) on the line of scrimmage and declare it ready for play.

Positions

The width of the spotted football defines the width of the neutral zone

Neutral zone (American football)

In American football, the neutral zone can be described as the length of the football from one tip to the other when it is spotted on the field prior to the snap of the ball during a scrimmage down...

, an area of the field no player other than the snapper may position himself in or above before the snap. Each team has its own line of scrimmage, thought of as a vertical plane from sideline to sideline that passes through the point of the ball nearest its own goal line.

The players on offense must arrange themselves in a formation

Formation (American football)

A formation in American football refers to the position players line up in before the start of a down. There are both offensive and defensive formations and there are many formations in both categories.-Offense:...

, all behind their line of scrimmage

Line of scrimmage

In American and Canadian football a line of scrimmage is an imaginary transverse line beyond which a team cannot cross until the next play has begun...

(that is, on their side of the ball). For reasons of safety and competitive balance, there are strict rules which define the way in which the offensive players may line up. Seven players must line up directly on the line of scrimmage, these are collectively referred to as linemen. Four players line up behind the line of scrimmage, these are collectively referred to as backs. Within this formation, there are six eligible receiver

Eligible receiver

In American football and Canadian football, not all players on offense are entitled to receive a forward pass. Only an eligible pass receiver may legally catch a forward pass, and only an eligible receiver may advance beyond the neutral zone if a forward pass which crosses the neutral zone is thrown...

s who may receive a forward pass

Forward pass

In several forms of football a forward pass is when the ball is thrown in the direction that the offensive team is trying to move, towards the defensive team's goal line...

during play. These eligible receivers are the four backs, and the two players at either end of the line. The remaining five linemen, often called interior linemen do not normally handle the ball during a play. Because of these rules, various leagues of American football have enacted strict rules of uniform numbering so officials may more easily judge which players were eligible and which were not at the start of a play. For example, 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...

, ineligible players wear numbers 50-79, while eligible receivers wear 1-49 or 80-99.

Even within this structure, offenses can still present a wide number of formations, so long as they maintain the "seven and four" arrangement. Ends, for example, may play close to the other linemen (called tight end

Tight end

The tight end is a position in American football on the offense. The tight end is often seen as a hybrid position with the characteristics and roles of both an offensive lineman and a wide receiver. Like offensive linemen, they are usually lined up on the offensive line and are large enough to be...

s) or they may play some distance down the line of scrimmage, where they are called split ends, or sometimes wide receiver

Wide receiver

A wide receiver is an offensive position in American and Canadian football, and is the key player in most of the passing plays. Only players in the backfield or the ends on the line are eligible to catch a forward pass. The two players who begin play at the ends of the offensive line are eligible...

s. Of the four backs, they may play behind the linemen, or may play "split out" to provide additional wide receivers. These additional receivers can be flanker

Flanker

Flanker may refer to:*The NATO reporting name for the Sukhoi Su-27 and derivatives:**Flanker-A: Sukhoi T-10 **Flanker-B: Sukhoi Su-27**Flanker-C: Sukhoi Su-30 **Flanker-D: Sukhoi Su-33...

s (if they play split far wide, but still in the backfield) or slot receivers if they play in the "slot" between the split end and the rest of the offensive line. One of the four backs receives the snap

Snap (football)

A snap starts each American football and Canadian football play from scrimmage.-Action:...

from the center

Center (American football)

Center is a position in American football and Canadian football . The center is the innermost lineman of the offensive line on a football team's offense...

. This player is called the quarterback

Quarterback

Quarterback is a position in American and Canadian football. Quarterbacks are members of the offensive team and line up directly behind the offensive line...

. The remaining members of the backfield are called a variety of names, depending on their intended role, such as running back

Running back

A running back is a gridiron football position, who is typically lined up in the offensive backfield. The primary roles of a running back are to receive handoffs from the quarterback for a rushing play, to catch passes from out of the backfield, and to block.There are usually one or two running...

, halfback

Halfback (American football)

A halfback, sometimes referred to as a tailback, is an offensive position in American football, which lines up in the backfield and generally is responsible for carrying the ball on run plays. Historically, from the 1870s through the 1950s, the halfback position was both an offensive and defensive...

, fullback

Fullback (American football)

A fullback is a position in the offensive backfield in American and Canadian football, and is one of the two running back positions along with the halfback...

, H-back

H-back

An H-Back is an offensive position in American football, and is also known as power back. The position is a hybrid of a fullback and a tight end. The position was made notable in the NFL by the Washington Redskins under head coach Joe Gibbs who ran a two tight end system...

, wingback

Wingback

Wingback has several uses.*Wing chair, a type of high-backed chair*In American football, the wingback is one of several varieties of running backs*In Association football, the wingback is a defensive position...

, or slotback

Slotback

Slotback is a position in Gridiron football . The slotback is similar to the wide receiver but also has many of the same traits as a running back, lines up closer to the offensive line and often farther back...

.

The players on defense may arrange themselves in any manner, as long as all players are "behind the line" (that is, on the side of the line nearest their own end zone). Players who line up opposite the offensive line are called defensive linemen, usually with one or two defensive tackles in the middle (a single defensive tackle is often called the nose guard or nose tackle) and with one defensive end

Defensive end

Defensive end is the name of a defensive position in the sport of American and Canadian football.This position has designated the players at each end of the defensive line, but changes in formations have substantially changed how the position is played over the years...

on each side. Behind the linemen are the linebackers. Positioned opposite the wide receivers are the cornerback

Cornerback

A cornerback is a member of the defensive backfield or secondary in American and Canadian football. Cornerbacks cover receivers, to defend against pass offenses and make tackles. Other members of the defensive backfield include the safeties and occasionally linebackers. The cornerback position...

s. Farthest back from the line are the safeties, usually in the middle of the field behind the linebackers. The linemen and linebackers, close to the line of scrimmage, are often referred to as playing "in the box", players outside "the box" (usually cornerbacks and safeties) are collectively referred to as the "secondary".

Starting the down

A scrimmage down begins with a snap, where the center throws or hands the ball backward to one of the backs, usually the quarterback

Quarterback

Quarterback is a position in American and Canadian football. Quarterbacks are members of the offensive team and line up directly behind the offensive line...

. The down ends when the ball becomes dead (see below). The ball is typically next spotted where the ball became dead; however, if it became dead outside the hash marks, it is brought in on the same yard line to the nearest hash mark. This spot becomes the line of scrimmage for the next play. In the case of an incomplete forward pass

Forward pass

In several forms of football a forward pass is when the ball is thrown in the direction that the offensive team is trying to move, towards the defensive team's goal line...

, the ball is returned to the spot where it was snapped to begin the previous play. A fumbled ball that goes out of bounds is declared dead and possession remains with the team that most recently had control of the ball.

Dead ball

The ball becomes dead, and the down ends, when:

the ball carrier is downed, as described above;
a forward pass falls incomplete (it touches the ground before possession is secured by a player);
the ball or ball carrier touches the sideline or end line or otherwise goes outside the field of play ("out of bounds");
the ball carrier or the ball, except on a scoring field goal attempt, hits any part of the goalpost (even if it bounces back onto the field);
a team scores;
a kick receiver makes a fair catch
Fair catch
A fair catch is a feature of American football and several other codes of football, in which a player attempting to catch a ball kicked by the opposing team – either on a kickoff or punt – is entitled to catch the ball without interference from any member of the kicking team...

(waving his arm above his head to signal a fair catch, where the kicking team is not allowed to interfere with him or hit him after the catch, but in return he is not allowed to run), or a member of the receiving team gains possession after a fair catch signal was given;
a member of the kicking team possesses a kicked ball beyond the line of scrimmage (e.g. "downing" a punt allowed to roll by the receiving team by holding it to stop its roll);
a kicked ball comes to rest;
a touchback occurs; or
under NFL or college rules, on fourth down (or, in the NFL, on any down after the two-minute warning in either half), a ball fumbled forward by the offensive team is recovered by an offensive team player other than the fumbler.

The nearest official typically blows his whistle after the ball becomes dead to alert the players that the down has already ended. If the ball is alive and the official sounds an inadvertent whistle, then the ball still becomes dead, but the team in possession of the ball may elect to have the down replayed or take the spot where the ball was declared dead. If the ball was loose from a fumble, then the ball can be put into play at the spot of the fumble. If the ball was in flight from a kick or a pass, then the down is always replayed.

Free kick downs

A free kick is a down which does not occur from scrimmage. The kicking team begins behind the ball, while the receiving team must remain at least 10 yards downfield before the ball is kicked.

Kickoffs

A kickoff is a type of free kick where the ball is placed on a tee (or held) at the kicking team's 30-yard line (40 for high school). In the 2011 NFL Season, changes were made regarding kickoffs to limit injuries. Kickoffs were returned from the 30-yard line to the 35-yard line, repealing a 1994 rule change. In addition, players on the kickoff coverage team cannot line up more than 5 yards behind the kickoff line, minimizing running starts and thus reducing the speed of collisions. The kicking team's players may not cross this line until the ball is kicked; members of the non-kicking (or "receiving") team are similarly restrained behind a line 10 yards further downfield (the 40-yard line, or 50 for high school). A valid kickoff must travel at least this 10-yard distance to the receiving team's restraining line, after which any player of either team may catch or pick up the ball and try to advance it (a member of the kicking team may only recover a kickoff and may not advance it) before being downed (see "Downed player," below). In most cases, the ball is kicked as far as possible (typically 40 to 70 yards), after which a player of the receiving team is usually able to secure possession (since the members of the kicking team cannot start downfield until after the ball is kicked). Occasionally, for tactical reasons, the kicking team may instead choose to attempt an onside kick, in which the kicker tries to kick the ball along the ground just over the required 10-yard distance in such a manner that one of his own teammates can recover the ball for the kicking side.if it is touched before ten yards, the ball is dead and a re-kick or spot of the ball will be rewarded to the receiving team.

Receiving a kickoff

A member of the receiving team gaining possession of the ball on a kickoff may attempt to advance it as far as he can toward the kicking team's goal line before being downed. Once the ball carrier is downed, the play is whistled dead and the ball is placed by the officials at the point where the play ended; this spot then becomes the line of scrimmage

Line of scrimmage

In American and Canadian football a line of scrimmage is an imaginary transverse line beyond which a team cannot cross until the next play has begun...

for the ensuing play. A kick that travels through or goes out of bounds within the end zone without being touched, or is caught by the receiving team in the end zone but not advanced out of it, results in a touchback

Touchback

In American football, a touchback is a ruling which is made and signaled by an official when the ball becomes dead behind or above a goal line and the team who is attacking that goal line is responsible for the ball being there. Responsibility is determined by which team gave the ball the impetus...

; the ball is then placed at the receiving team's 20-yard line, which becomes the line of scrimmage.

A kickoff that goes out of bounds anywhere other than the end zone before being touched by the receiving team is an illegal kick: the receiving team has the option of having the ball re-kicked from five yards closer to the kicking team's goal line, or they may choose to take possession of the ball at the point where it went out of bounds or 30 yards from the point of the kick (25 yards in high school), whichever is more advantageous.

Other free kicks

A free kick is also used to restart the game following a safety. The team that was trapped in its own end zone, therefore conceding two points to the other team, kicks the ball from its own 20-yard line. This can be a place kick (in the NFL, a tee cannot be used), drop kick or punt.

In the NFL and high school, a free kick may be taken on the play immediately after a fair catch

Fair catch

A fair catch is a feature of American football and several other codes of football, in which a player attempting to catch a ball kicked by the opposing team – either on a kickoff or punt – is entitled to catch the ball without interference from any member of the kicking team...

; see "fair catch kick" below.

Field goal (3 points)

A field goal is scored when the ball is place kicked, drop kicked, or free kicked after a fair catch or awarded fair catch (High School or NFL only) between the goal posts behind the opponent's end zone. The most common type of kick used is the place kick. For a place kick, the ball must first be snapped to a placeholder, who holds the ball upright on the ground with his fingertip so that it may be kicked. Three points are scored if the ball crosses between the two upright posts and above the crossbar and remains over. If a field goal is missed, the ball is returned to the original line of scrimmage (in the NFL, to the spot of the kick; in high school, to the 20-yard line if the ball enters the end zone, or otherwise where the ball becomes dead after the kick) or to the 20-yard line if that is further from the goal line, and possession is given to the other team. If the ball does not go out of bounds, the other team may catch the kicked ball and attempt to advance it, but this is usually not advantageous. One official is positioned under each goalpost; if either one rules the field goal no good, then the field goal is unsuccessful. A successful field goal is signaled by an official extending both arms vertically above the head. A team that successfully kicks a field goal kicks off to the opposing team on the next play.

Touchdown (6 points)

A touchdown is achieved when a player has legal possession of the ball and the ball crosses an imaginary vertical plane above the opposing team's goal line. After a touchdown, the scoring team attempts a try for 1 or 2 points (see below). A successful touchdown is signaled by an official extending both arms vertically above the head.

For statistical purposes, the player who advances the ball into or catches it in the end zone is credited with the touchdown. If a forward pass was thrown on the play, the quarterback is also credited with a passing touchdown.

Try for extra point (1 or 2 points)

A try is more frequently called an extra-point attempt or a PAT (abbreviation of "Point After Touchdown"). Either one or two additional points may be scored during the try. The ball is spotted at the 2 yard line (NFL) or 3 yard line (college/high school), and the team is given one untimed play to earn points:

The offensive team may attempt to kick the ball through the goalposts, in the same manner that a field goal is kicked. This option is almost always chosen, because a two point conversion attempt is much riskier. If successful the team is awarded one point, referred to as an extra point
Convert
The convert or try, in American football known as "point after", and Canadian football "Point after touchdown", is a one-scrimmage down played immediately after a touchdown during which the scoring team is allowed to attempt to score an extra one point by kicking the ball through the uprights , or...

. Because the extra point is almost always successful (especially in NFL play), sportscasters will refer to a team up or trailing by seven (not six) points as being "up/trailing by a touchdown".

The offensive team may attempt to advance the ball via run or pass into the end zone, much like a touchdown on the extra-point attempt, except that it receives two points. This is called a two-point conversion
Two-point conversion
In American and Canadian football, a two-point conversion is a play a team attempts instead of kicking a one-point convert immediately after it scores a touchdown...

. The success rate for two-point conversions is less than 40 percent in the NFL and college, making the two-point conversion attempt a risky tactic; thus it is usually attempted only when two points will help the team but one point will not.
- For example, suppose that it is late in the game with a score of 21-10 and the losing team scores a touchdown, making the score 21-16. The scoring team will usually attempt the two-point conversion, because if successful, a three-point deficit later could be matched with one field goal; failure to convert would result in a five-point deficit that could not be surmounted without another touchdown—a situation no worse than the four-point deficit achieved with a kicked extra point.
- Another example would be if a team scores a late-game touchdown, and as a result is down by two points. A successful two-point conversion would tie the game, and likely force overtime. In very rare and risky instances, a trailing team who scored a touchdown, and as a result is down by 1 point, may attempt a two-point conversion to gamble on a win and avoid overtime (or, under NCAA or NFHS rules, a subsequent overtime period). Two famous examples of this gamble were by Nebraska
  1983 Nebraska Cornhuskers Football Team
  The 1983 Nebraska Cornhuskers football team represented the University of Nebraska–Lincoln] in the 1983 NCAA Division I-A football season. The team was coached by Tom Osborne and played their home games in Memorial Stadium in Lincoln, Nebraska...
  
  in the last minute of the 1984 Orange Bowl
  1984 Orange Bowl
  The 1984 Orange Bowl was the 50th annual Orange Bowl Classic, played on January 2, 1984, between the unbeaten Nebraska Cornhuskers and the once-beaten Miami Hurricanes, for the national championship. After leading 31-17 in the fourth quarter, Miami held on for a 31-30 victory...
  
  (unsuccessful) and by Boise State
  2006 Boise State Broncos football team
  The 2006 Boise State Broncos football team represented Boise State University in the 2006 college football season. The Broncos won the Western Athletic Conference championship with an undefeated 12–0 regular-season record , their second unbeaten regular season in the past three years...
  
  in the first overtime of the 2007 Fiesta Bowl
  2007 Fiesta Bowl
  The 2007 Tostitos Fiesta Bowl was a college football bowl game played as part of the 2006–2007 Bowl Championship Series of the 2006 NCAA Division I FBS football season...
  
  (successful). Note that under NCAA rules, teams are required to "go for two" starting with the third overtime procedure.

Under college rules, if the defensive team gains possession and advances the ball the length of the field into the opposite end zone on the try (for example by an interception or a fumble recovery, or by blocking a kick and legally recovering the ball), they score two points. This is officially recorded as a touchdown scored by the defense. The NCAA
National Collegiate Athletic Association
The National Collegiate Athletic Association is a semi-voluntary association of 1,281 institutions, conferences, organizations and individuals that organizes the athletic programs of many colleges and universities in the United States...

adopted this rule in 1990.
- This scenario cannot occur under NFL or high school football
  National Federation of State High School Associations
  The National Federation of State High School Associations is the body that writes the rules of competition for most high school sports and activities in the United States. Most high schools, whether public or private, belong to their state's high school association; in turn, each state association...
  
  rules; the ball is ruled dead and the try is over immediately when the defense gains possession.

In the extremely rare event that the offensive team scores a safety on the try, it receives one point. In college football, this can occur when, for example, the defense gains control of the ball and attempts to advance it, then fumbles it out of bounds in its own end zone. In the NFL, since the try ends once the defense gains possession, a safety can only be scored if a defensive player bats a loose (fumbled) ball out of bounds in the end zone.

The game clock is not advanced during a try, however, the play clock is enforced. A delay of game penalty, false start, or similar penalty, by the offense results in a 5-yard penalty assessed for the try. Typically, penalties charged against the defense give the offensive two options: half the distance to the goal for the try, or assessing the full penalty on the ensuing kickoff. Since the try is not timed by the game clock, if a touchdown is scored as regulation time expires (and game clock subsequently reads :00), the try is still allowed to be conducted. This instance is relatively common as teams score a game-tying (or game-winning) extra point after regulation has expired.
- During sudden-death overtime, particularly in the NFL, if a team scores a touchdown in the overtime period, the game is immediately over, and the try is not attempted.
- In NCAA overtime, if the second team to possess the ball in the overtime scores a touchdown which puts them ahead of the opponent in points the game ends immediately and no try is attempted.

The officials' signal for a successful try, whether an extra point or a two point conversion, is the same as for a touchdown. After the try, the team that scored the touchdown kicks off to the opposing team.

Safety (2 points)

The uncommon safety is scored if a player causes the ball to become dead in his own end zone; two points are awarded to the opposing (usually defending) team. This can happen if a player is either downed or goes out of bounds in the end zone while carrying the ball, or if he fumbles the ball, and it goes out of bounds in the end zone. A safety is also awarded to the defensive team if the offensive team commits a foul which is enforced in its own end zone. A safety is not awarded if a player intercepts a pass or receives a kick in his own end zone and is downed there. This situation, in which the opponent caused the ball to enter the end zone, is called a touchback

Touchback

; no points are scored, and the team that gained possession of the ball is awarded possession at its own 20 yard line. If the interception or reception occurs outside the end zone, and the player is carried into the end zone by momentum, the ball is placed at the spot of the catch and no safety is awarded. A safety is signaled by a referee holding both palms together above the head, fingertips pointing upwards. After a safety, the team that conceded the safety kicks a free kick (which may be a punt, place kick, or drop kick) from its 20 yard line.

Fair catch kick (High school or NFL only, 3 points)

A free kick (see above) may be taken on the play immediately after any fair catch

Fair catch

of a punt. In the NFL, if the receiving team elects to attempt this and time expired during the punt, the half is extended with an untimed down. The ball must be held on the ground by a member of the kicking team or may be drop kicked; a tee may not be used. (High school kickers may use a tee.) This is both a field goal attempt and a free kick; if the ball is kicked between the goal posts, three points are scored for the kicking team. This is the only case where a free kick may score points. This method of scoring is extremely rare; it is only advantageous when a team catches a very short punt with very little time left. Note that a team is unlikely to be punting with only a few seconds left in a half, and it is rarer still for punts to be caught near field goal range. The officials' signal for a successful fair catch kick is the same as for a field goal.

Officials

The game is officiated by a crew of three to seven officials. Every crew will consist of a referee, who is generally in charge of the game and watches action on the quarterback and in the offensive backfield; an umpire, who handles spotting the ball and watches action on the offensive line; and a head linesman, who supervises placement of the down box and line-to-gain chains. The crew may also consist of a line judge, back judge, field judge and side judge, in the order listed: i.e. a crew of five officials has a referee, umpire, head linesman, line judge and back judge.

Officials are selected by the teams in advance or appointed by the governing league. Note that unlike some other sports, no football officials—not even at the NFL level—are full-time employees of the league; they all officiate on a part-time basis. In the other three major North American professional sports leagues--Major League Baseball

Major League Baseball

Major League Baseball is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League...

, the NBA

National Basketball Association

The National Basketball Association is the pre-eminent men's professional basketball league in North America. It consists of thirty franchised member clubs, of which twenty-nine are located in the United States and one in Canada...

and NHL

National Hockey League

The National Hockey League is an unincorporated not-for-profit association which operates a major professional ice hockey league of 30 franchised member clubs, of which 7 are currently located in Canada and 23 in the United States...

--officials are employed by their respective leagues. The sheer volume of games in the other three sports necessitates full-time officials; the NFL regular season is only 16 games long, compared to 162 games for MLB and 82 for the NBA and NHL.

During the game, the officials are assisted in the administration of the game by other persons, including: a clock operator to start and stop the game clock (and possibly also the play clock); a 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...

who hold the down indicator and the line-to-gain chains on the sideline; and ball boys, who provide footballs to officials between downs (e.g. a dry ball each down on a wet day). These individuals may be provided by the teams involved—it is common for a high school coach's son or daughter to act as ball boy for the team.

Fouls and their penalties

Because football is a high-contact sport

Contact sport

Many sports involve a degree of player-to-player or player-to-object contact. The term "contact sport" is used in both team sports and combat sports, medical terminology and television game shows, such as the Gladiators and Wipeout, to certain degrees...

requiring a balance between offense and defense, many rules exist that regulate equality, safety, contact, and actions of players on each team. It is very difficult to always avoid violating these rules without giving up too much of an advantage. Thus, an elaborate system of fouls and penalties has been developed to "let the punishment fit the crime" and maintain a balance between following the rules and keeping a good flow of the game. Players are constantly looking for ways to find an advantage that stretches the limitations imposed by the rules. Also, the frequency and severity of fouls can make a large difference in the outcome of a game, so coaches are constantly looking for ways to minimize the number and severity of infractions committed by their players.

It is a common misconception that the term "penalty" is used to refer both to an infraction and the penal consequence of that infraction. A foul is a rule infraction for which a penalty is prescribed. Some of the more common fouls are listed below. In most cases when a foul occurs, the offending team will be assessed a penalty of 5, 10 or 15 yards, depending on the foul. Also, in most cases, if the foul is committed while the ball is in play, the down will be replayed from the new position (for example, if the offense commits a foul on a first-down play, the next play will still be first down, but the offense may have to go 15 yards, or farther, to achieve another first down.) But if a defensive foul results in the ball advancing beyond the offense's first-down objective, the next play will be the first down of a new series. Some penalties (typically for more serious fouls), however, require a loss of down for the offense; and some defensive fouls may result in an automatic first down regardless of the ball position. In all cases (except for ejection of a player or, in rare cases, forfeiture of the game), the non-offending team is given the option of declining the penalty and letting the result of the play stand (although the Referee may exercise this option on their behalf when it is obvious), if they believe it to be more to their advantage. For some fouls by the defense, the penalty is applied in addition to the yardage gained on the play. Most personal fouls, which involve danger to another player, carry 15-yard penalties; in rare cases, they result in offending players being ejected from the game. In the NFL, if a defensive foul occurs after time has expired at the end of a half, the half will be continued for a single, untimed play from scrimmage. Under college rules, any accepted penalty when time has expired at the end of any quarter results in an extension for one untimed down.

In the NFL, with three exceptions, no penalty may move the ball more than half the distance toward the penalized team's goal line. These exceptions are defensive pass interference (see the discussion of that foul for more details), intentional grounding, and offensive holding – but in this last case the exception pertains only if the infraction occurs within the offensive team's own end zone, in which case an automatic safety is assessed (intentional grounding from the end zone also carries an automatic safety). Under college rules, the same half-the-distance principle applies, but any offensive fouls involving contact in their end zone (e.g. holding, illegal blocking or personal fouls) result in a safety.

Note: The neutral zone is the space between the two free-kick lines during a free-kick down and between the two scrimmage lines during a scrimmage down. For a free-kick down, the neutral zone is 10 yards wide and for a scrimmage down it is as wide as the length of the football. It is established when the ball is marked ready for play. No player may legally be in the neutral zone except for the snapper on scrimmage downs, and no one except the kicker and the holder for free kick downs.

Timeouts

Each team receives three timeouts per half (if the game goes to overtime, each team receives additional timeouts), making for a total of six timeouts per team in a regulation game. Timeouts received in the first half may not be used in the second half or overtime. In professional football, a team must have at least one remaining timeout to challenge an official's call.

Instant replay

In the NFL, a number of rulings can be reviewed by officials or challenged by coaches (see Instant replay). If a coach wants to challenge a play, he must do so before the next play begins, and he does so by throwing a red flag similar to the officials' yellow flags. Coaches are allowed two challenges per game and are granted a third if their first two are successful. The team loses a timeout if they lose the challenge. Therefore, they cannot challenge if they do not have timeouts. Plays within the two-minute-warning and overtime cannot be challenged; any review must be initiated by a replay official off-field. The referee performs the actual review via a video screen on the sideline. The referee will announce the result of instant replay

Instant replay

Instant replay is the replaying of video footage of an event or incident very soon after it has occurred. In television broadcasting of sports events, instant replay is often used during live broadcast, to show a passage of play which was important or remarkable, or which was unclear on first...

reviews over his wireless microphone.

Beginning in the 2011 NFL Season, An instant replay review by the booth official will now be automatic for every play ruled by the referees on the field to have scored points. This is seen as another step in the "modernization" of sports. Every scoring play will be reviewed now, which saves coaches from using up their challenges on close plays in the endzone.

In college, coaches are allowed one challenge per game by first requesting a timeout. Otherwise, a replay official in the press box observes all plays. If he deems a ruling may be in error, he notifies the officials on the field to interrupt the game before the beginning of the next play. The replay official performs the review and relays the decision to the referee, who announces the result. Not every conference employs replay, which is optional.

High school rules do not provide for video review of any decisions by officials during the game. Further, the use of television or video tape for coaching purposes during the game is prohibited. If a coach feels a rule has been misinterpreted, he may call timeout and request a coach-referee conference to discuss the ruling with the referee, but no replay equipment will be consulted during the conference.

External links

National Football League Digest of Rules
National Football League Beginner's Guide to Football
National Football League Official Signals
National Collegiate Athletic Association Football Rules and Interpretations

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.