American football

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Sometimes known outside of North America as Gridiron Football, American Football is a sport in which two teams fight for control of an oblate spheroid ball (a direct descendant of a size 3 rugby ball), which they have to carry in the arms and/or pass to another player (only one forward pass permitted per football play.

American football is played at several levels in the United States: from Pop Warner youth leagues to teams from high schools to teams from colleges and universities (popularly known as College Football) to teams of professional players. The most prominent professional league is the National Football League in the United States. Other leagues appear from time to time, such as the XfL. In the 1960s, American football replaced baseball as the most popular sport in the United States.

Field of Play

The game is played on a rectangular field that is 100 yards long and 53 1/3 yards wide. The sidelines are the end boundaries that run 100 yards along the length of the rectangle. At each end of the rectangle, 100 yards apart from each other, are the goal lines.

Yard lines are painted, every five yards, across the length of the field to identify the distance from the goal lines. At midfield is located the 50 yard line, and from there the line numbers are counted downward in each direction towards the two goal lines. In addition, hash marks are painted along the sideline to identify the individual yards that fall between the successive 5 yard lines.

Behind each goal line is a 10 yard deep rectangular area known as the end zone. Although a football play never begins in an end zone, it is possible for a play to take place there after the ball is snapped. At the rear of the end zone is a set of goal posts.

Play Of The Game (NFL rules)

Each team places eleven players on the field during the course of play. A game is 60 minutes long, and is divided into two halves and four quarters. The game begins with a kick off, in which one team kicks the ball from their own 30-yard line. The ball must be kicked from the ground (not punted) and in bounds at least 10 yards away, or else the receiving team takes possession of the ball thirty yards away from the original spot of the kick off. The ball is live and can be fielded by either team, but because it is generally difficult for the kicking team to successfully recover the kick, the kicking team normally kicks the ball to the other team as far as possible toward the opposition goal line. If a team instead kicks the ball the minimum ten yards and tries to recover their own kick, this is known as an onside kick, and is usually only attempted when the team is behind in the score late in the game.

The team in possession of the ball is given four attempts (known as "downs") to move the ball a total of 10 yards towards the opposition end of the field. Each new play begins at the yard line where the previous play ended; this is known as the line of scrimmage. Succesfully reaching ten yards results in the awarding of four more downs to make another ten yards. A new set of four downs is known as a first down. Failure in achieving a first down results in the possesion of the ball being handed to the opposition at current line of scrimmage. If a team has not achieved a first down by the third attempt, it may decide to kick the ball away on the fourth one (this is known as a punt), rather than running a normal play to advance the ball. The purpose of punting is to put the opponent in worse field position than they would be through turning the ball over at the line of scrimmage after a fourth down failure to achieve a new first down.

If the ball is moved over the opposition's goal line (into the "End Zone") whilst in possesion of a player a "touchdown", worth 6 points, is scored. Scoring a touchdown entitles the team to a kick at goal (for one point) a single play for the End Zone (a two-point conversion). After a score, the scoring team restarts play with a kick off.

A team can also score three points by kicking the ball between the goalposts. This is known as a field goal. Teams normally only attempt to kick a field goal if it is fourth down, or if time is running out in the half or the game. Field goal attempts must be made with the ball touching the ground, so one player holds the ball on the ground steady while another player kicks it. Failed field goal attempts can be returned by the opponent, but this is rare; normally, the ball is turned over to the other team at the line of scrimmage. After a successful field goal, the scoring team then issues a kick off.

A kick off also occurs at the start of the second half.

If a player in possession of the ball is tackled in his own end zone, this is a safety, worth two points to the other team. The team that was in possession of the ball must then kick it away from their own 20 yard line. Normally, this is done with a punt.

The team with possesion is called the "offensive team", and that without the "defensive team". Typically two distinct corps of players are used for these two roles. All field players are allowed to be substituted for after any play; players may re-enter the game after any play.

Moving the Ball

There are two basic methods of moving the ball down the field.

  • A forward pass from behind the line of scrimmage, usually thrown by the quarterback. If the ball is caught by a player on the offense (without bouncing) this is a "complete pass", and the next down takes place wherever he is tackled. After a forward pass all passes must be lateral passes or rearward passes. If the forward pass is caught by a member of the defense, this is an "interception", and play continues with possesion relinquished by the offense.
  • Running the ball. The ball is handed to a player on the offense who attempts to run with it down the field. The next down takes place from where he is tackled. If the ball is dropped (a "fumble") before the player is tackled, possesion is given by whichever team recovers control of the loose ball.

Penalties

Rules infractions during a previous play result in the offending team being penalized a certain amount of yards. Normally, the down number remains the same as it was before the previous play, unless a defensive penalty causes a first down to take place. Certain types of penalties require a loss of down, however. In addition, unless the penalty took place before the play actually started, the opposing team normally has the option of declining a penalty if the result of the previous play was more beneficial to it than the yard penalization would be. Referees signal an infraction by throwing a yellow flag onto the field.

Rules infractions which involve the details of of game protocol are considered less serious than personal fouls, which involve physical actions which could endanger other players.

The half and the end of the game cannot end on a defensive penalty. In that case, the offense gets another play even though time has run out.

Common penalties include:

  • Offside (5 yards). Both teams must remain on their own side of the line of scrimmage before a play starts.
  • False Start (5 yards). Also known as illegal procedure. There are strict rules that govern when and how players on the offensive team may move prior to the start of a play. If an offensive lineman moves prior to the start of a play, this is a penalty.
  • Illegal motion (5 yards). Similar to a false start, this offensive penalty specifically pertains to eligible receivers, only one of whom is allowed to move when the play starts, and even then laterally to the line of scrimmage.
  • Holding (10 yards). This penalty occurs when a player illegally uses his hands when blocking or trying to slow down an opponent.
  • Illegal block in the back (15 yards). Also known as clipping, a player may not block another player from behind
  • Face mask (5 or 15 yards). Grabbing an opponent's face mask is a 15 yard personal foul. Incidentally grabbing and releasing the face mask is a 5 yard penalty. Touching an opponent's face mask without grabbing it, such as a player using the stiff-arm technique, is not illegal.
  • Pass Interference. Offensive and defensive players have the right to attempt to catch a ball. Pushing or grabbing a player to prevent them from attempting to catch it is illegal.
  • Roughing the passer (15 yards). Deliberately tackling or hitting a player (usually the quarterback) after he has thrown a forward pass.
  • Intentional downing (10 yards and loss of down). Deliberately throwing an incomplete forward pass in order to avoid being tackled behind the line of scrimmage.

Positions

Teams are usually divided into three specialist groups: offense, defense and special teams. The offense plays when the team has possession of the ball and attempts to score: the other team's defense attempts to stop them. Special teams are generally involved in kicking situations, either to score points or for field position. Summaries of positions are given here: more detail can be found on individual pages.

Offense

  • Quarterback: Usually the 'leader' on offense, the quarterback or QB is the first player to handle the ball after the beginning of a play. He generally either passes the ball to a receiver or hands it off to a running back.
  • Halfback: One of the running back positions. Halfbacks are usually the main runners on their team and often also act as short-yardage receivers.
  • Fullback: A bit of a jack-of-all-trades and the other running back position, the fullback usually does a bit of running, a bit of receiving and a bit of blocking, either to defend the quarterback or to open up holes for another running back.
  • Tight End: Another jack-of-all-trades, the tight end is a mixture of receiver and offensive lineman who may be called upon to block or to catch passes.
  • Offensive Tackle: The lineman at the end of the line. Generally their job is to protect the quarterback from defenders coming around the outside of the line or open up holes for running backs.
  • Guard: Offensive linemen who play inside the tackles. Again, they protect the quarterback and open up holes for running backs. Guards may sometimes also be expected to pull, or move to the opposite side of the line, in support of certain kinds of plays.
  • Center: The final offensive line position, this player is sandwiched between the guards. In addition to the usual duties of linemen, he snaps the ball to the quarterback to start a play.


Defense

  • Defensive End: One of the two defensive line positions. Defensive ends play on the outside of the defensive line and are supposed to stop outside rushing plays and to put pressure on the quarterback on passing plays.
  • Defensive Tackle: The interior defensive line position. Defensive tackles have similar duties to defensive ends but with the emphasis on stopping inside rushing plays.
  • Linebacker: Linebackers play behind the defensive line and may perform various duties, including tackling running backs who make it past the defensive line, tackling receivers after short passes and pressuring the quarterback.
  • Cornerback: The cornerback's main duty is to stop receivers, either by preventing them from catching passes or else tackling them after a catch.
  • Safety: Traditionally the last line of defense, although safeties are often brought up close to the line of scrimmage against teams with strong running backs.

Special Teams

  • Place Kicker: A player who specialises in kicking field goals and who may also be responsible for kick-offs.
  • Punter: A player who specialises in kicking the ball in such a way as to get the best possible field position for his team if the team runs out of downs before getting into scoring range for the place kicker. May also be responsible for kick-offs.
  • Punt Returner: A player who specialises in catching and returning a punted ball as far as possible. Most punt returners also play another role on the team.
  • Kick Returner: Much like a punt returner, except that he specialises in returning kick-offs rather than punts.
  • Holder: A player who receives the long snap and quickly places the ball on the ground for the place kicker on field goal tries. A substitute quarterback will often be the Holder.

You may read and write about individual teams on their respective pages.


/Glossary

References:

Penalties : http://www.nfl.com/fans/rules/penaltysummaries.html

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