American football

American football, known as gridiron football or simply football in North America, is a widely followed sport that originated in the United States of America. The game is played by both amateurs and professionals on a 100- by 55-yard field with two end zones that are 10 yards deep. The goal of the game is to score the most points in the alloted time, primarily by advancing the ball into the opponent's end zone. Teams usually consist of 11 players per side.

The National Football League is the premier professional football league in the world, with all teams located in the United States.

Basic rules

Each team is given four chances, called "downs", to try to move the ball a minimum of 10 yards. To do this, they must either run with the ball towards the end zone, or they may pass the ball. If they are successful, they are given a new set of four downs to try again. This process continues until they either either score a touchdown or attempt a field goal. Immediately after a team scores a touchdown, they have the option to try adding one or two additional points. In either case, the ball is placed two yards outside of the end zone. If the team decides to attempt adding one point, they must kick the ball through the goal posts as they would for a field goal. To add two points, the team must bring the ball back into the end zone in one play.

If the team is unsuccessful in moving the ball 10 yards or more in four downs, possession of the ball is given to the other team. Often times, if a team is not able to attain a "first down" after three downs, and they are too far away from the end zone to kick a field goal, they will use their fourth down to "punt" the ball. A punt is an attempt to move the starting position of the other team back by means of kicking the ball. If this is done, the team making the punt must relinquish possession of the ball; they are not allowed to use any yards gained by this method towards their 10 yards.

Once the original game time has expired, if one team has more points than the other, then they are declared the winners. If there is a tie, there are different methods used to determine the winner based on what level or league the game is being played on. In the NFL, a new block of 15 minutes is added to the clock and the two teams compete as normal, with the initial possession being determined by means of a coin toss. The first team to score any amount of points is instantly the winner. If after the additional 15 minutes no team has scored, the game stops and is declared a tie.

Methods of scoring

Touchdown

A touchdown is worth 6 points. A touchdown is scored when a player has possession of the ball and the ball crosses the goal line of the opposing team's end zone. Touchdowns can be scored on offense, defense, and special teams.

Point after touchdown

A point after touchdown (PAT), or extra point, is worth 1 point. A team can elect to attempt a PAT after they score a touchdown. A PAT is scored when the football is kicked between the goalposts, which stand directly behind the end zone. The line of scrimmage is placed at the 2 yard line for a PAT, and the ball is kicked from the 9 yard line.

2-Point conversion

A 2-point conversion is an alternative to the PAT that is worth 2 points. After a touchdown, the scoring team can execute 1 offensive play attempting to cross into the end zone. The line of scrimmage is the 2 yard line.

Field goal

A field goal is worth 3 points, and is scored when the offensive team kicks the ball between the goalposts. This can be attempted anywhere on the field.

Safety

A safety occurs when a defensive player tackles an offensive player in their own end zone and are worth 2 points. The team scoring the safety is also awarded the ball on the following kickoff.

Positions

Standard American football is played with 11 players on offense and 11 players on defense.

Offense

• Quarterback-Takes the snap, and hands the ball of to a running back to run, or makes a pass.
• Halfback -(also known as a Runningback). Usually the best running back on the team, the halfback gets most of the handoffs in the running game. Often lines up the furthest in the backfield.
• Fullback-On running plays, usually acts as a blocker for the halfback, although he may get the ball in short yardage situations.
• Tackle-Offensive line position; cannot handle the ball. There are 2 tackles, right and left, who align at the edge of the offensive line. Tackles are generally the best pass-blockers on the team, because they must block the opposing defensive end, who is usually the best pass-rusher.
• Guard-Offensive line. There are 2 guards, left and right, who align between the center and the tackle on their side.
• Center-Offensive line. Plays at the center of the line, and snaps the ball at the beginning of the play.
• Tight End-The tight end lines up on the line of scrimmage, and usually blocks on running plays, and acts as a receiver on passing plays. Some are very good receivers, whereas some excel more as blockers.
• Wide Receiver-The best receivers on the field. They usually align several yards outside of the offensive line, their primary role is to get open on passing downs.

Defense

• Defensive Tackle-Defensive linemen, they line up in the middle of the defensive line. Also known as a "nose tackle". Usually the biggest defensive players.
• Defensive End-Defensive linemen, they line up outside of the defensive tackles. Often the best pass-rushers on a team.
• Outside Linebacker-Linebackers that line up to the outside. In a 4-3 defense, they are aligned directly behind a defensive end, in a 3-4 defense they align well to the outside of the line. Usually the better pass coverage linebackers.
• Inside Linebacker-Linebackers that align in the middle of the field. They are usually the best tacklers and run-stoppers.
• Cornerback-The cornerback is a defensive back, and is responsible for covering one of the other team's wide receivers. There are usually 2 on the field at a time. Often the fastest defensive player on a team, but may not be a very good tackler.
• Strong Safety-The safety that lines up on the side of the offense's tight end, generally 7-10 yards from the line of scrimmage. Strong safeties vary widely in their skill, with some "hard hitting" safeties who excel primarily at coming up to stop the run, while others excel more at pass coverage, playing deep zone coverages, or lining up on a man (usually the tight end).
• Free Safety-The safety that aligns on the side opposite of the offense's tight end, usually 8-12 yards downfield. The free safety often plays a deep zone in case one of the cornerbacks or linebackers gets beaten.
• Nickleback-The nickelback is a fifth pass defender that is added to the formation in some passing situations. He is normally listed as a cornerback. He often replaces a linebacker, but sometimes replaces a Defensive lineman instead.
• Dimeback-The Dimeback is a sixth pass defender or fourth cornerback that is brought into the game when the defensive team wants to defend strongly against the pass. Like the Nickleback, he typically replaces a linebacker from the standard formation.

Special teams

• Place Kicker The kicker is the player who attempts to kick the ball through the goal posts on field goals and point after touchdowns. Typically they are also the one who kicks the kick-off which is used at the start of the half and after every score. With all of these types of plays, the ball is kicked from a stationary, vertical position, either being held by another player, or while sitting on a stand.
• Punter The punter is the player who punts the ball. Punts are not taken from a stationary position, instead, the ball is snapped to the punter, who then will drop-kick the ball.