American football is a team sport played in the United States of America (USA) played by two teams of eleven players on a rectangular field with goalposts at each end. In the United States and Canada, American football is also known as gridiron. The terms gridiron or American football are favoured in English-speaking countries where other types of football are popular, such as the United Kingdom, Ireland, New Zealand, and Australia
American football is played much like soccer as the team which has the ball in their possession runs towards the opponent’s goal with the ball in their hands as the attacking team passes the ball to each other trying to score a goal. The other team that is the defensive team tries to stop the attacking team from scoring a goal by blocking them and gaining possession of the ball.
In American football, points are scored primarily by advancing the ball into the opposing team’s end zone for a touchdown or kicking the ball through the opponent’s goalposts for a field goal. The team with the most points at the end of a game wins.
American football is the most popular sport in the United States of America. It is a widely popular sport in College sports and High school sports. American football is a mixture of soccer and rugby and the game evolved in the United States of America (USA) during the 1800s. The first American football match was played on November 6, 1869, between two college teams, Rutgers and Princeton, using rules based on the rules of soccer at the time.
Walter Camp, who is also known as the Father of American Football, established the snap, the line of scrimmage, eleven-player teams, and the concept of downs, from 1880 onwards. The National Football League (NFL) is the most popular American football league in the USA. Its championship game, the Super Bowl, ranks among the most-watched club sporting events in the world. The league has an annual revenue of around US$10 billion.
Primarily, American football has been a mixture of rugby and soccer. On the first impression, the game looks very much similar to what is rugby. Rugby, like American football, is a sport where two competing teams vie for control of a ball, which can be kicked through a set of goalposts or run into the opponent’s goal area to score points.
The first American football match was played on November 6, 1869, between two college teams, Rutgers and Princeton, using rules based on the rules of soccer at the time. They consisted of 25 players each and used a round ball that could not be picked up or carried. It could, however, be kicked or batted with the feet, hands, head or sides, with the objective being to advance it into the opponent’s goal. Rutgers won the game 6–4.
Representatives of Yale, Columbia, Princeton and Rutgers met on October 19, 1873, to create a standard set of rules for use by all schools. Teams were set at 20 players each, and fields of 400 by 250 feet (122 m × 76 m) were specified.
Walter Camp, who is also known as the Father of American Football, made some changes to the rules in 1880 and reduced the size of each team from 15 to 11 players and instituted the snap to replace the chaotic and inconsistent scrum. The introduction of the snap resulted in an unexpected consequence. Prior to the snap, the strategy had been to punt if a scrum resulted in bad field position.
However, a group of Princeton players realized that as the snap was uncontested, they could now hold the ball indefinitely to prevent their opponent from scoring.
The move prompted a rule change to prevent this strategy from taking hold, and a reversion to the scrum was considered. However, Camp successfully proposed a rule in 1882 that limited each team to three downs, or tackles, to advance the ball 5 yards (4.6 m). Failure to advance the ball the required distance within those three downs would result in control of the ball being forfeited to the other team.
This change effectively made American football a separate sport from rugby, and the resulting five-yard lines added to the field to measure distances made it resemble a gridiron in appearance.
Other major rule changes included a reduction of the field size to 110 by 53 1⁄3 yards (100.6 m × 48.8 m) and the adoption of a scoring system that awarded four points for a touchdown, two for a safety and a goal following a touchdown, and five for a goal from the field. Additionally, tackling below the waist was legalized, and a static line of scrimmage was instituted.
However, these rule changes were not enough to remove the dangers of the sport. American football remained to be a dangerous sport in the USA. A lot of injuries and deaths took place because of some serious formations that were still existent in American football. The then American President, Theodore Roosevelt, threatened to ban the game throughout the country if some serious changes in the rules were not introduced.
In response, 62 colleges and universities met in New York City to discuss rule changes on December 28, 1905. These proceedings resulted in the formation of the Intercollegiate Athletic Association of the United States, later renamed the National Collegiate Athletic Association (NCAA).
Other rule changes introduced that year included the reduction of playing time from 70 to 60 minutes and an increase of the distance required for a first down from 5 to 10 yards (4.6 to 9.1 m). A neutral zone was created along the width of the football before the snap. The field was also shortened to 100 yards (91 m) long, but two 10-yard-long (9.1 m) end zones were created, and teams were given four downs instead of three to advance the ball 10 yards (9.1 m).
Professional football came into the foray slowly and gradually as rising salaries and unpredictable player movement became a part of the game. The National Football League (NFL), a group of professional teams that was originally established in 1920 which became the centre point of professional American football in the country. By 1922, the NFL had established itself as America’s premier professional football league.
In the early 1960s, the American Football League (AFL), helped American football become the most popular sport in the USA. The rival AFL arose in 1960 and challenged the NFL’s dominance. The AFL’s existence forced the conservative NFL to expand to Dallas and Minnesota in an attempt to destroy the new league.
Meanwhile, the AFL introduced many new features to professional football in the United States: official time was kept on a scoreboard clock rather than on a watch in the referee’s pocket, as the NFL did; optional two-point conversions bypass or run after touchdowns; names on the jerseys of players; and several others, including the expansion of the role of minority players, actively recruited by the league in contrast to the NFL.
The AFL also signed several star college players who had also been drafted by NFL teams. Competition for players heated up in 1965 when the AFL New York Jets signed rookie Joe Namath to a then-record $437,000 contract (equivalent to $2.71 million in 2018.
The bidding war for players ended in 1966 when NFL owners approached the AFL regarding a merger, and the two leagues agreed on one that took full effect in 1970. This agreement provided for a common draft that would take place each year, and it instituted an annual World Championship game to be played between the champions of each league.
This championship game began play at the end of the 1966 season. Once the merger was completed, it was no longer a championship game between two leagues and reverted to the NFL championship game, which came to be known as the Super Bowl.
A football game is played between two teams of 11 players each. Playing with more on the field is punishable by a penalty. Teams may substitute any number of their players between downs. Individual players in a football game must be designated with a uniform number between 1 and 99. NFL teams are required to number their players by a league-approved numbering system, and any exceptions must be approved by the Commissioner.
The entire offensive unit in American football is aimed at advancing the ball down the field of play and clinching more points by way of more touchdowns. For an offensive lineup to snap the ball, they must be in a legal formation. An offensive formation is considered illegal if there are more than four players in the backfield or fewer than five players numbered 50–79 on the offensive line.
Players can line up temporarily in a position whose eligibility is different from what their number permits as long as they report the change immediately to the referee, who then informs the defensive team of the change. Neither team’s player, except the centre (C), is allowed to line up in or cross the neutral zone until the ball is snapped. Interior offensive linemen are not allowed to move until the snap of the ball.
The main backfield positions are the quarterback (QB), halfback/tailback (HB/TB) and fullback (FB). The quarterback is the leader of the offence. Either the quarterback or a coach calls the plays. Quarterbacks typically inform the rest of the offence of the play in the huddle before the team lines up. The quarterback lines up behind the centre to take the snap and then hands the ball off, throws it or runs with it.
The primary role of the halfback, also known as the running back or tailback, is to carry the ball on running plays. Halfbacks may also serve as receivers. Fullbacks tend to be larger than halfbacks and function primarily as blockers, but they are sometimes used as runners in short-yardage situations and are seldom used in passing situations.
The offensive line (OL) consists of several players whose primary function is to block members of the defensive line from tackling the ball carrier on running plays or sacking the quarterback on passing plays. The leader of the offensive line is the centre, who is responsible for snapping the ball to the quarterback, blocking and for making sure that the other linemen do their jobs during the play. On either side of the centre are the guards (G), while tackles (T) line up outside the guards.
The principal receivers are the wide receivers (WR) and the tight ends (TE). Wide receivers line up on or near the line of scrimmage, split outside the line. The main goal of the wide receiver is to catch passes thrown by the quarterback but they may also function as decoys or as blockers during running plays. Tight ends line up outside the tackles and function both as receivers and as blockers.
The role of the defence is to prevent the offence from scoring by tackling the ball carrier or by forcing turnovers (interceptions or fumbles).
The defensive line (DL) consists of defensive ends (DE) and defensive tackles (DT). Defensive ends line up on the ends of the line, while defensive tackles line up inside, between the defensive ends. The primary responsibilities of defensive ends and defensive tackles are to stop running plays on the outside and inside, respectively, to pressure the quarterback on passing plays, and to occupy the line so that the linebackers can breakthrough.
Linebackers line up behind the defensive line but in front of the defensive backfield. They are divided into two types: middle linebackers (MLB) and outside linebackers (OLB). Linebackers are the defensive leaders and call the defensive plays. Their diverse roles include defending the run, pressuring the quarterback, and guarding backs, wide receivers and tight ends in the passing game.
The defensive backfield often called the secondary, consists of cornerbacks (CB) and safeties (S). Safeties are themselves divided into free safeties (FS) and strong safeties (SS). Cornerbacks line up outside the defensive formation, typically opposite a receiver to be able to cover them. Safeties line up between the cornerbacks but farther back in the secondary. Safeties are the last line of defence and are responsible for stopping deep passing plays as well as running plays.
The special teams unit is responsible for all kicking plays. The special teams unit of the team in control of the ball tries to execute field goal (FG) attempts, punts and kickoffs, while the opposing team’s unit will aim to block or return them.
Three positions are specific to the field goal and PAT (point-after-touchdown) unit: the placekicker (K or PK), holder (H) and long snapper (LS). The long snapper’s job is to snap the football to the holder, who will catch and position it for the placekicker.
There is not usually a holder on kickoffs, because the ball is kicked off a tee; however, a holder may be used in certain situations, such as if the wind is preventing the ball from remaining upright on the tee. The player on the receiving team who catches the ball is known as the kickoff returner (KR).
The positions specific to punt plays are the punter (P), long snapper, upback and gunner. The long snapper snaps the football directly to the punter, who then drops and kicks it before it hits the ground. The Gunners line up split outside the line and race down the field, aiming to tackle the punt returner (PR)—the player who catches the punt. The Upbacks line up a short distance behind the line of scrimmage, providing additional protection to the punter.
In American football, the team which has scored more points until the final whistle wins the game. The most valuable manner of scoring points in American football is the touchdown. The touchdown is worth six points and apart from it; there are a plethora of ways in which points can be scored in American football. A touchdown is scored when a live ball is advanced into, caught in, or recovered in the opposing team’s end zone.
The scoring team then attempts a try or conversion, more commonly known as the point(s)-after-touchdown (PAT), which is a single scoring opportunity. A PAT is most commonly attempted from the two- or three-yard line, depending on the level of play. If a PAT is scored by a placekick or dropkick through the goalposts, it is worth one point, typically called the extra point. If it is scored by what would normally be a touchdown it is worth two points, typically called the two-point conversion.
A Field Goal (FG) is scored when the ball is placekicked or dropkicked through the uprights of over the crossbar of the opponents’ goalpost. A Field Goal is worth three points. A safety is scored when the ball carrier is tackled in their own end zone. Safeties are worth two points, which are awarded to the defence. In addition, the team that conceded the safety must kick the ball to the scoring team via a free-kick.
The fields in which football games are rectangular in shape and measure 120 yards (110m) long and 53 1⁄3 yards (48.8 m) wide. Lines marked along the ends and sides of the field are known as the end lines and sidelines. Goal lines are marked 10 yards (9.1 m) inward from each end line.
Goalposts are located at the centre of the plane of the two end lines. The crossbar of these posts is 10 feet (3.0 m) above the ground, with vertical uprights at the end of the crossbar 18 feet 6 inches (5.64 m) apart for professional and collegiate play, and 23 feet 4 inches (7.11 m) apart for the high school play. The uprights extend vertically 35 feet (11 m) on professional fields, a minimum of 10 yards (9.1 m) on college fields, and a minimum of 10 feet (3.0 m) on high school fields.
Goalposts are padded at the base, and orange ribbons are normally placed at the tip of each upright as indicators of wind strength and direction.
The football itself is an oval ball, similar to the balls used in rugby or Australian football. At all levels of play, the football is inflated to 12 1⁄2 to 13 1⁄2 pounds per square inch (86 to 93 kPa) and weighs 14 to 15 ounces (400 to 430 g); beyond that, the exact dimensions vary slightly. In the professional play, the ball has a long axis of 11 to 11 1⁄4 inches (28 to 29 cm), a long circumference of 28 to 28 1⁄2 inches (71 to 72 cm), and a short circumference of 21 to 21 1⁄4 inches (53 to 54 cm).
In college and high school play the ball has a long axis of 10 7⁄8 to 11 7⁄16 inches (27.6 to 29.1 cm), a long circumference of 27 3⁄4 to 28 1⁄2 inches (70 to 72 cm), and a short circumference of 20 3⁄4 to 21 1⁄4 inches (53 to 54 cm).
The total duration of an American football game is 60 minutes at the college and professional level, with the entire duration being divided into two halves of 30 minutes each and four quarters of 15 minutes each. The total duration in High school football is 48 minutes, with two halves of 24 minutes each and four quarters of 12 minutes each.
The halftime is the break period between the two halves, while the first and third quarters are followed by shorter breaks. Games last longer than their defined length due to play stoppages—the average NFL game lasts slightly over three hours. Time in a football game is measured by the game clock. An operator is responsible for starting, stopping and operating the game clock based on the direction of the appropriate official.
A separate play clock is used to determine if a delay of game infraction has been committed. If the play clock expires before the ball has been snapped or free-kicked, a delay of game foul is called on the offence. The play clock is set 25 seconds after certain administrative stoppages in play and to 40 seconds when play is proceeding without such stoppages.
An American football game starts with both the captains coming together for a coin toss which is held by the referee. It is the visiting team that can call either heads or tails during the coin toss and whichever captain wins the toss, whether to receive or kick off the ball or which goal they wish to defend.
They can defer their choice until the second half. Unless the winning team decides to defer, the losing team chooses the option the winning team did not select—to receive, kick, or select a goal to defend to begin the second half.
Most teams choose to receive or defer because choosing to kick the ball to start the game allows the other team to choose which goal to defend. Teams switch goals following the first and third quarters. If a down is in progress when a quarter ends, play continues until the down is completed.
Officials are responsible for enforcing game rules and monitoring the clock. All officials carry a whistle and wear black-and-white striped shirts and black hats except for the referee, whose hat is white. Each carries a weighted yellow flag that is thrown to the ground to signal that a foul has been called. An official who spots multiple fouls will throw their hat as a secondary signal.
The officials in an American football match are:
- The referee is the man in charge of an American football game. He is charged with oversight and control of the game and is the authority on the score, the down number, and any rule interpretations in discussions among the other officials. The referee announces all penalties and discusses the infraction with the offending team’s captain, monitors for illegal hits against the quarterback, makes requests for first-down measurements, and notifies the head coach whenever a player is ejected. The referee positions themselves to the passing arm side of the quarterback. In most games, the referee is responsible for spotting the football prior to a play from scrimmage.
- The umpire watches play along the line of scrimmage to make sure that no more than 11 offensive players are on the field before the snap and that no offensive linemen are illegally downfield on pass plays. The umpire monitors contact between offensive and defensive linemen and calls most of the holding The umpire records the number of timeouts taken and the winner of the coin toss and the game score, assists the referee in situations involving possession of the ball close to the line of scrimmage, determines whether player equipment is legal, and dries wet balls prior to the snap if a game is played in rain.
- The back judge is positioned deep in the defensive backfield, behind the umpire. The back judge ensures that the defensive team has no more than 11 players on the field and determines whether catches are legal, whether field goal or extra point attempts are good, and whether a pass interference violation occurred. The back judge is also responsible for the play clock, the time between each play when a visible play clock is not used.
- The head linesman/down judge is positioned on one end of the line of scrimmage. The head linesman/down judge watches for any line-of-scrimmage and illegal use-of-hands violations and assists the line judge with illegal shift or illegal motion calls. The head linesman/down judge also rules on out-of-bounds calls that happen on their side of the field, oversees the chain crew and marks the forward progress of a runner when a play has been whistled dead.
- The side judge is positioned twenty yards downfield of the head linesman. The side judge mainly duplicates the functions of the field judge. On-field goal and extra point attempts, the side judge is positioned lateral to the umpire.
- The line judge is positioned on the end of the line of scrimmage, opposite the head linesman. They supervise player substitutions, the line of scrimmage during punts, and game timing. The line judge notifies the referee when the time has expired at the end of a quarter and notifies the head coach of the home team when five minutes remain for halftime. In the NFL, the line judge also alerts the referee when two minutes remain in the half. If the clock malfunctions or becomes inoperable, the line judge becomes the official timekeeper.
- The field judge is positioned twenty yards downfield from the line judge. The field judge monitors and controls the play clock counts the number of defensive players on the field and watches for offensive pass interference and illegal use-of-hands violations by offensive players. The field judge also makes decisions regarding catches, recoveries, the ball spot when a player goes out of bounds, and illegal touching of fumbled balls that have crossed the line of scrimmage. On-field goal and extra point attempts, the field judge is stationed under the upright opposite the back judge.
- The centre judge is an eighth official used only at the top level of college football. The centre judge stands lateral to the referee, the same way the umpire does in the NFL. The centre judge is responsible for spotting the football after each play and has many of the same responsibilities as the referee, except announcing penalties.
The National Football League (NFL) and the National Collegiate Athletic Association (NCAA) are the most popular football leagues in the United States. The National Football League was founded in 1920 and has since become the largest and most popular sport in the United States.
The NFL championship game is called the Super Bowl and is among the biggest events in club sports worldwide. It is played between the champions of the National Football Conference (NFC) and the American Football Conference (AFC), and its winner is awarded the Vince Lombardi Trophy.