American football

A set of rule changes drawn up from 1880 onward by Walter Camp, the "Father of American Football", established the snap, the line of scrimmage, eleven-player teams, and the concept of downs.

The sport is closely related to Canadian football, which evolved in parallel with and at the same time as the American game, although its rules were developed independently from those of Camp.

Rugby, like American football, is a sport in which 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.

[13] Princeton, Harvard, Yale, and Columbia then agreed to intercollegiate play using a form of rugby union rules with a modified scoring system.

[21] A 1905 peak of 19 fatalities nationwide resulted in a threat by President Theodore Roosevelt to abolish the game unless major changes were made.

[24] 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).

Despite these extra benefits, the game had a strict sense of amateurism at the time, and direct payment to players was frowned upon, if not prohibited outright.

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 by pass or run after touchdowns; names on the jerseys of players; and several others, including expansion of the role of minority players, actively recruited by the league in contrast to the NFL.

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 $4.23 million in 2023).

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.

[59] The leader of the offensive line is the center, who is responsible for snapping the ball to the quarterback, blocking,[59] and for making sure that the other linemen do their jobs during the play.

The main goal of the wide receiver is to catch passes thrown by the quarterback,[59] but they may also function as decoys or as blockers during running plays.

Turnovers include interceptions (a defender catching a forward pass intended for the offense) and forced fumbles (taking possession of the ball from the ball-carrier).

Their roles include defending the run, pressuring the quarterback, and tackling backs, wide receivers, and tight ends in the passing game.

[54] 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).

Goal posts are padded at the base, and orange ribbons are normally placed at the tip of each upright as indicators of wind strength and direction.

[79] To contain the compressed air within it, a pig's bladder was commonly used before the advent of artificial rubber inside the leather outer shell to sustain crushing forces.

[80][81] At all levels of play, the football is inflated to 12+1⁄2 to 13+1⁄2 psi (86 to 93 kPa), or just under one atmosphere, and weighs 14 to 15 ounces (400 to 430 g);[78][82][83] beyond that, the exact dimensions vary slightly.

The visiting team can call either "heads" or "tails"; the winner of the toss chooses whether to receive or kick off the ball or which goal they wish to defend.

[124] Repeated concussions (and possibly sub-concussive head impacts[128]) can increase a person's risk in later life for CTE (chronic traumatic encephalopathy) and health issues such as dementia, Parkinson's disease, and depression.

Originally not intended as a rival league, the entry of owners who sought marquee talent and to challenge the NFL led to an escalation in salaries and ensuing financial losses.

[154] The United Football League (UFL) began in 2009 but folded after suspending its 2012 season amid declining interest and lack of major television coverage.

[156] American football leagues exist throughout the world, but the game has yet to achieve the international success and popularity of baseball and basketball.

[163][164] The continuing interest and growth in both the sport and the series has led to the possible formation of a potential NFL franchise in London[165][166][167] An American football league system already exists within the UK, the BAFANL, which has run under various guises since 1983.

The day on which the Super Bowl is held is considered a de facto national holiday,[185] and in parts of the country like Texas, the sport has been compared to a religion.

[196] Japan was introduced to the sport in 1934 by Paul Rusch, a teacher and Christian missionary who helped to establish football teams at three universities in Tokyo.

The NFL has expressed interest in having games in the country, and the Super Bowl has become a widely watched event in Brazil at bars and movie theaters.

[206][207] China has additionally been a target for the expansion of the sport, with the Mainland being the home of the Chinese National Football League as well as a growing audience of Super Bowl watchers.

[209] Although both games share a similar set of rules, there are several key rule differences: for example, in Canadian football the field measures 150 by 65 yards (137 by 59 m), including two 20-yard end zones (for a distance between goal lines of 110 yards),[210] teams have three downs instead of four, there are twelve players on each side instead of eleven,[211] fair catches are not allowed, and a rouge, worth a single point is scored if the offensive team kicks the ball out of the defense's end zone.

Walter Camp standing by the railing on a bridge
Walter Camp , the "Father of American Football", in 1878 when Camp was captain of Yale University's football team
Cartoon showing a figure with a skeletal head holding a football upright with extended arms while lying down on a football field
The dangers associated with the sport depicted in a 1908 cartoon by William Charles Morris
Photo of William Heffelfinger
Pudge Heffelfinger , widely regarded as the first professional football player
Diagram showing a green background with a white horizontal line dividing it into two-halves, with eleven small blue squares representing defense players in a formation above the line, and eleven small red circles representing offense players in another formation below the line, with two text captions "Defense" and "Offense", the former placed above the line and the latter below the line
A diagram of a typical pre-snap formation. The offense (red) is lined up in a variation of the I formation , while the defense (blue) is lined up in the 4–3 defense . Both formations are legal.
A quarterback for the Kiel Baltic Hurricanes under center, ready to take the snap
Photograph of defensive players tackling an offensive player who has just lost control of the football
Dallas Cowboys defensive players force Houston Texans running back Arian Foster to fumble the ball.
Four players run up the field as the kicker executes a kickoff
Kicker Jeff Reed of the Pittsburgh Steelers executes a kickoff.
A player pursued by an opponent dives into the end zone in front of an official to score a touchdown.
A player for the Navy Midshipmen (dark jersey) scores a touchdown while a defender from the Tulsa Golden Hurricane (in white) looks on. The goal line is marked by the small orange pylon.
Photograph of a football field taken from the end zone showing goal posts in the foreground
A football field as seen from behind one end zone. The tall, yellow goal posts mark where the ball must pass for a successful field goal or extra point. The large, rectangular area marked with the team name is the end zone.
A quarterback is shown in the process of throwing a forward pass. His offensive linemen are in front of him.
Carolina Panthers quarterback Jake Delhomme (number 17) in the motion of throwing a forward pass
A placekicker attempts a field goal by kicking the ball from the hands of a holder.
Tampa Bay Buccaneers placekicker Connor Barth attempts a field goal by kicking the ball from the hands of a holder. This is the standard method to score field goals or extra points. [ 103 ] [ 104 ]
Seven officials are pictured meeting at the infield. Officials meeting at midfield
Officials meeting at midfield
Officials are using a chain to measure for a first down.
Officials use the chains to measure for a first down. Here, the ball is just short of the pole and therefore short of a first down.
Photograph of a down indicator box on a pole
A modern down indicator box is mounted on a pole and is used to mark the current line of scrimmage. The number on the marker is changed using a dial.
Photograph of a player wearing a helmet, with shoulder pads and thigh pads visible under their uniform
Vince Agnew wearing a helmet with his shoulder pads and thigh pads visible under his uniform
Photograph of a Mexican youth division football team
Players with one of the youth divisions of the Borregos Salvajes football program of the Monterrey Institute of Technology and Higher Education , Mexico City
The Boise State Broncos are the first football team to design a blue field in 1986.
Photograph of London's Wembley Stadium during the opening ceremony of the 2010 NFL International series showing the field and the stands filled with fans
Opening ceremony of the 2010 NFL International Series at London's Wembley Stadium
A 2012 football game between national teams of Finland and Sweden at Sonera Stadium (now Bolt Arena) in Helsinki
Photograph of men playing flag football
Men playing a game of flag football