American football

From Wikipedia, the free encyclopedia

Jump to navigationJump to search
This article is about the American variation of gridiron football. For other uses,
see American football (disambiguation).

American football

Larry Fitzgerald (in blue) catches a pass while Cortland

Finnegan (in red) plays defense at the 2009 Pro Bowl.

Highest governing body International Federation of

American Football

Football
Nicknames
gridiron
First played November 6, 1869
New Brunswick, New Jersey,
United States
(Princeton vs. Rutgers)

Characteristics
Contact Full
 Team members 11 (both teams
may freely substitute players
between downs)
Type Team sport
ball game
Equipment Football
Football helmet
Pads (shoulder, thigh, knee,
and optionally elbow pads)
Venue Football field (rectangular: 120
yards long, 53 1⁄3 yards wide)
Glossary Glossary of American football

Presence
Country or region Worldwide (most popular in
North America)
Olympic No (demonstrated at the 1932
Summer Olympics)[1]
World Games Yes (invitational sport
at 2005 and 2017 Games).

American football, referred to simply as football in the United States and Canada, and
also known as gridiron,[nb 1] is a team sport played by two teams of eleven players on a
rectangular field with goalposts at each end. The offense, the team with possession of
the oval-shaped football, attempts to advance down the field by running with the ball
or passing it, while the defense, the team without possession of the ball, aims to stop
the offense's advance and to take control of the ball for themselves. The offense must
advance at least ten yards in four downs or plays; if they fail, they turn over the football
to the defense, but if they succeed, they are given a new set of four downs to continue
the drive. 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 evolved in the United States, originating from the sports
of soccer and rugby. 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. 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. Later rule changes legalized
the forward pass, created the neutral zone and specified the size and shape of the
football. 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. Most of the features that distinguish American
 football from rugby and soccer are also present in Canadian football. The two sports are
considered the primary variants of gridiron football.
American football is the most popular sport in the United States. The most popular
forms of the game are professional and college football, with the other major levels
being high school and youth football. As of 2012, nearly 1.1 million high school athletes
and 70,000 college athletes play the sport in the United States annually. The National
Football League, the most popular American professional football league, has
the highest average attendance of any professional sports league in the world. 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$15 billion, making
it the most valuable sports league in the world. Other professional leagues exist
worldwide, but the sport does not have the international popularity of other American
sports like baseball or basketball.

Contents

 1Etymology and names

 2History
o 2.1Early history
o 2.2Evolution of the game
o 2.3Professional era
 3Teams and positions
o 3.1Offensive unit
o 3.2Defensive unit
o 3.3Special teams unit
 4Rules
o 4.1Scoring
o 4.2Field and equipment
o 4.3Duration and time stoppages
o 4.4Advancing the ball and downs
o 4.5Kicking
o 4.6Officials and fouls
 5Safety and brain health
 6Leagues and tournaments
o 6.1Other professional leagues
 6.1.1Rival leagues
 6.1.2Complementary national leagues
o 6.2International play
 7Popularity and cultural influence
o 7.1United States
o 7.2Other countries
 8Variations and related sports
 9See also
 10Notes
 11Footnotes
 12References
 13Further reading
 14External links

Etymology and names

Main article: Football (word)
In the United States, American football is referred to as "football". [4] The term "football"
was officially established in the rulebook for the 1876 college football season, when the
sport first shifted from soccer-style rules to rugby-style rules. Although it could easily
have been called "rugby" at this point, Harvard, one of the primary proponents of the
rugby-style game, compromised and did not request the name of the sport be changed
to "rugby".[5] The terms "gridiron" or "American football" are favored in English-speaking
countries where other types of football are popular, such as the United Kingdom,
Ireland, New Zealand, and Australia. [6][7]

History
Main articles: History of American football and American football in the United States

Part of the American football series on the

History of American football

Origins of American football

 Early history
 First game
 Walter Camp
 First pro player
 First pro league
 Modern history

Close relations to other codes

 Medieval
 Old division
 Rugby league
 Rugby union
 Soccer
 Canadian
  Australian rules football

Topics
 Black players in professional football
 Homosexuality
 Concussions
 Rugby union comparison
 Rugby league comparison
 Canadian football comparison
 Pro Football Hall of Fame
 College Football Hall of Fame
 Years 
o NFL seasons
o College football seasons
 Glossary

 American football Portal

 v
 t
 e

Early history
American football evolved from the sports of rugby and soccer. 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. [8]
What is considered to be the first American football game was played on November 6,
1869, between Rutgers and Princeton, two college teams. They consisted of 25 players
per team 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. [9][10] Collegiate play
continued for several years with matches played using the rules of the host school.
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. Harvard abstained from
the conference, as they favored a rugby-style game that allowed running with the ball.
[10]
 After playing McGill University using both Canadian and American rules, the Harvard
players preferred the Canadian style of having only 11 men on the field, running the ball
without having to be chased by an opponent, the forward pass, tackling, and using an
oblong instead of a round ball.[11][12]
An 1875 Harvard–Yale game played under rugby-style rules was observed by two
Princeton athletes who were impressed by it. They introduced the sport to Princeton, a
feat the Professional Football Researchers Association compared to
"selling refrigerators to Eskimos".[10] Princeton, Harvard, Yale, and Columbia then agreed
to intercollegiate play using a form of rugby union rules with a modified scoring system.
[13]
 These schools formed the Intercollegiate Football Association, although Yale did not
join until 1879. Yale player Walter Camp, now regarded as the "Father of American
Football",[13][14] secured rule changes in 1880 that reduced the size of each team from 15
to 11 players and instituted the snap to replace the chaotic and inconsistent scrum.[13]
Evolution of the game

A photograph of Walter Camp, the "Father of American Football", taken in 1878 when Camp was
captain of Yale's football team

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. In 1881, in a game between Yale
and Princeton, both teams used this strategy to maintain their undefeated records. Each
team held the ball, gaining no ground, for an entire half, resulting in a 0–0 tie. This
"block game" proved extremely unpopular with both teams' spectators and fans. [13]
A rule change was necessary 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, [13] and a static line of
scrimmage was instituted.[15]
1908 cartoon (by W.C. Morris) highlighting the dangers that were associated with the sport

Despite these new rules, football remained a violent sport. Dangerous mass-formations
like the flying wedge resulted in serious injuries and deaths.[16] A 1905 peak of 19
fatalities nationwide resulted in a threat by President Theodore Roosevelt to abolish the
game unless major changes were made. [17] 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).[18]
The legal forward pass was introduced in 1906, although its effect was initially minimal
due to the restrictions placed on its use. The idea of a 40-yard-wider field was opposed
by Harvard due to the size of the new Harvard Stadium.[19] 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). To
reduce infighting and dirty play between teams, the neutral zone was created along the
width of the football before the snap.[20] Scoring was also adjusted: points awarded for
field goals were reduced to three in 1909 [14] and points for touchdowns were raised to six
in 1912.[21] Also in 1912, the field was shortened to 100 yards (91 m) long, 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).[22][23] The roughing the passer penalty was
implemented in 1914, and eligible players were first allowed to catch the ball anywhere
on the field in 1918.[24]
Professional era
Pudge Heffelfinger, widely regarded as the first professional football player

A team from the Indiana Soldiers' and Sailors' Children's Home, 1896.

On November 12, 1892, Pudge Heffelfinger was paid $500 to play a game for

the Allegheny Athletic Association in a match against the Pittsburgh Athletic Club. This
is the first recorded instance of a player being paid to participate in a game of American
football, although many athletic clubs in the 1880s offered indirect benefits, such as
helping players attain employment, giving out trophies or watches that players could
pawn for money, or paying double in expense money. 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. [25]
Over time, professional play became increasingly common, and with it came rising
salaries and unpredictable player movement, as well as the illegal payment of college
players who were still in school. The National Football League (NFL), a group of
professional teams that was originally established in 1920 as the American Professional
Football Association, aimed to solve these problems. This new league's stated goals
included an end to bidding wars over players, prevention of the use of college players,
and abolition of the practice of paying players to leave another team. [26] By 1922, the
NFL had established itself as America's premier professional football league. [27]
The dominant form of football at the time was played at the collegiate level. The upstart
NFL received a boost to its legitimacy in 1925, however, when an NFL team,
the Pottsville Maroons, defeated a team of Notre Dame all-stars in an exhibition game.
[28]
 A greater emphasis on the passing game helped professional football to distinguish
itself further from the college game during the late 1930s. [26] Football, in general, became
increasingly popular following the 1958 NFL Championship game, a match between
the Baltimore Colts and the New York Giants that is still referred to as the "Greatest
Game Ever Played". The game, a 23–17 overtime victory by the Colts, was seen by
millions of television viewers and had a major influence on the popularity of the sport.
This, along with the innovations introduced by the new American Football League (AFL)
in the early 1960s, helped football to become the most popular sport in the United
States by the mid-1960s.[29]
The rival AFL arose in 1960 and challenged the NFL's dominance. The AFL began in
relative obscurity but eventually thrived, with an initial television contract with
the ABC television network. 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 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. 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 $2.79 million in 2020[30]). A five-year,
$40 million NBC television contract followed, which helped to sustain the young league.
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.[31]
College football maintained a tradition of postseason bowl games. Each bowl game was
associated with a particular conference and earning a spot in a bowl game was the
reward for winning a conference. This arrangement was profitable, but it tended to
prevent the two top-ranked teams from meeting in a true national championship game,
as they would normally be committed to the bowl games of their respective
conferences. Several systems have been used since 1992 to determine a national
champion of college football. The first was the Bowl Coalition, in place from 1992 to
1994. This was replaced in 1995 by the Bowl Alliance, which gave way in 1997 to
the Bowl Championship Series (BCS).[32] The BCS arrangement proved to be
controversial, and was replaced in 2014 by the College Football Playoff (CFP).[33][34]

Teams and positions

Main article: American football positions
A football game is played between two teams of 11 players each. [35][36][37] Playing with
more on the field is punishable by a penalty. [35][38][39] Teams may substitute any number of
their players between downs;[40][41][42] this "platoon" system replaced the original system,
which featured limited substitution rules, and has resulted in teams utilizing specialized
offensive, defensive and special teams units.[43]
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.[35] NCAA and NFHS teams are "strongly advised" to number their
offensive players according to a league-suggested numbering scheme. [44][45]
Although the sport is played almost exclusively by men, women are eligible to play in
high school, college, and professional football. No woman has ever played in the NFL,
but women have played in high school and college football games. [46] In 2018, 1,100 of
the 225,000 players in Pop Warner Little Scholars youth football were girls, and around
11% of the 5.5 million Americans who report playing tackle football are female
according to the Sports and Fitness Industry Association. [47] Women can also serve as
officials; Sarah Thomas became the NFL's first female official in 2015.[48]
Offensive unit
The role of the offensive unit is to advance the football down the field with the ultimate
goal of scoring a touchdown.[49]

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

The offensive team must line up in a legal formation before they can snap the ball. 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. [36][50]
[51]
 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.[52] Neither team's players, except
the center (C), are 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. [53]
A quarterback for the Kiel Baltic Hurricanes under center, ready to take the snap

The main backfield positions are the quarterback (QB), halfback/tailback (HB/TB)

and fullback (FB). The quarterback is the leader of the offense. Either the quarterback
or a coach calls the plays. Quarterbacks typically inform the rest of the offense of the
play in the huddle before the team lines up. The quarterback lines up behind the center
to take the snap and then hands the ball off, throws it or runs with it. [49]
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[54] and are seldom used in passing situations. [55]
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.[54] The leader of the offensive line is the
center, who is responsible for snapping the ball to the quarterback, blocking, [54] and for
making sure that the other linemen do their jobs during the play. [56] On either side of the
center 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).[57] 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, [54] 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. [54]
Defensive unit

Dallas Cowboys defensive players force Houston Texans running back Arian Foster to fumble the

ball

The role of the defense is to prevent the offense from scoring by tackling the ball carrier
or by forcing turnovers (interceptions or fumbles).[49]
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 break through.[54]

Cornerback Brent Grimes of the Hamburg Sea Devils intercepts a pass

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. [58]
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).[54] 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 defense and are responsible
for stopping deep passing plays as well as running plays. [54]
Special teams unit

Kicker Jeff Reed of the Pittsburgh Steelers executes a kickoff

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. [49]
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 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).[59]
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. 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. Upbacks line up a short distance behind the line of scrimmage,
providing additional protection to the punter. [60]

Rules
Main article: American football rules
Scoring

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

In football, the winner is the team that has scored more points at the end of the game.
There are multiple ways to score in a football game. The touchdown (TD), worth six
points, is the most valuable scoring play 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.[49] 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 goal posts, 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. In general, the extra point
is almost always successful while the two-point conversion is a much riskier play with a
higher probability of failure; accordingly, extra point attempts are far more common than
two-point conversion attempts.[61]
A field goal (FG), worth three points, is scored when the ball is placekicked or
dropkicked through the uprights and over the crossbars of the defense's goalposts. [62][63]
[64]
 After a PAT attempt or successful field goal, the scoring team must kick the ball off to
the other team.[65]
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 defense. [49] In addition, the team that
conceded the safety must kick the ball to the scoring team via a free kick.[66]
Field and equipment
Main article: American football field

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

Football games are played on a rectangular field that measures 120 yards (110 m) 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.[67][68][69]
Weighted pylons are placed the sidelines on the inside corner of the intersections with
the goal lines and end lines. White markings on the field identify the distance from the
end zone. Inbound lines, or hash marks, are short parallel lines that mark off 1-yard
(0.91 m) increments. Yard lines, which can run the width of the field, are marked every 5
yards (4.6 m). A one-yard-wide line is placed at each end of the field; this line is marked
at the center of the two-yard line in professional play and at the three-yard line in
college play. Numerals that display the distance from the closest goal line in yards are
placed on both sides of the field every ten yards. [67][68][69]
Goalposts are located at the center 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 high school play.[70][71][72] 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. 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.[70][71][72]
The football itself is an oval ball, similar to the balls used in rugby or Australian rules
football.[73] 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);[72][74][75] beyond that, the
exact dimensions vary slightly. In 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).[76] 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).[72][74]
Duration and time stoppages
Football games last for a total of 60 minutes in professional and college play and are
divided into two halves of 30 minutes and four quarters of 15 minutes. [77][78] High school
football games are 48 minutes in length with two halves of 24 minutes and four quarters
of 12 minutes.[79] The two halves are separated by a halftime period, and the first and
third quarters are followed by a short break.[77][78][80] Before the game starts, the referee
and each team's captain meet at midfield for a coin toss. 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. 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. [81] Teams switch
goals following the first and third quarters. [82] If a down is in progress when a quarter
ends, play continues until the down is completed. [83][84][85]
Games last longer than their defined length due to play stoppages—the average NFL
game lasts slightly over three hours.[86] 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.[77][87] A separate play clock is used to
show the amount of time within which the offense must initiate a play. The play clock is
set to 25 seconds after certain administrative stoppages in play and to 40 seconds
when play is proceeding without such stoppages. If the offense fails to start a play
before the play clock reads "00", a delay of game foul is called on the offense.[83][88][89]
Advancing the ball and downs

Carolina Panthers quarterback Jake Delhomme (number 17) in the motion of throwing a forward

pass

There are two main ways the offense can advance the ball: running and passing. In a
typical play, the center passes the ball backwards and between their legs to the
quarterback in a process known as the snap. The quarterback then either hands the ball
off to a back, throws the ball, or runs with it. The play ends when the player with the ball
is tackled or goes out-of-bounds or a pass hits the ground without a player having
caught it. A forward pass can be legally attempted only if the passer is behind the line of
scrimmage; only one forward pass can be attempted per down. [65] As in rugby, players
can also pass the ball backwards at any point during a play.[90] In the NFL, a down also
ends immediately if the runner's helmet comes off. [91]
The offense is given a series of four plays, known as downs. If the offense advances ten
or more yards in the four downs, they are awarded a new set of four downs. If they fail
to advance ten yards, possession of the football is turned over to the defense. In most
situations, if the offense reaches their fourth down they will punt the ball to the other
team, which forces them to begin their drive from farther down the field; if they are
in field goal range, they might attempt to score a field goal instead. [65] A group of officials,
the chain crew, keeps track of both the downs and the distance measurements. [92] On
television, a yellow line is electronically superimposed on the field to show the first down
line to the viewing audience.[93]
Kicking

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. [94][95]

There are two categories of kicks in football: scrimmage kicks, which can be executed
by the offensive team on any down from behind or on the line of scrimmage, [96][97][98] and
free kicks.[99][100][101] The free kicks are the kickoff, which starts the first and third quarters
and overtime and follows a try attempt or a successful field goal; the safety kick follows
a safety.[97][102][103]
On a kickoff, the ball is placed at the 35-yard line of the kicking team in professional and
college play and at the 40-yard line in high school play. The ball may be drop-kicked or
place-kicked. If a place kick is chosen, the ball can be placed on the ground or a tee; a
holder may be used in either case. On a safety kick, the kicking team kicks the ball from
their own 20-yard line. They can punt, drop-kick or place-kick the ball, but a tee may not
be used in professional play. Any member of the receiving team may catch or advance
the ball. The ball may be recovered by the kicking team once it has gone at least ten
yards and has touched the ground or has been touched by any member of the receiving
team.[104][105][106]
The three types of scrimmage kicks are place kicks, drop kicks, and punts. Only place
kicks and drop kicks can score points.[62][63][64] The place kick is the standard method used
to score points,[94] because the pointy shape of the football makes it difficult to reliably
drop kick.[94][95] Once the ball has been kicked from a scrimmage kick, it can be advanced
by the kicking team only if it is caught or recovered behind the line of scrimmage. If it is
touched or recovered by the kicking team beyond this line, it becomes dead at the spot
where it was touched.[107][108][109] The kicking team is prohibited from interfering with the
receiver's opportunity to catch the ball. The receiving team has the option of signaling
for a fair catch, which prohibits the defense from blocking into or tackling the receiver.
The play ends as soon as the ball is caught and the ball may not be advanced. [110][111][112]
Officials and fouls
See also: Official (American football), Chain crew, and Penalty (gridiron football)
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.

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.[113] The seven officials (of a standard seven-man
crew; lower levels of play up to the college level use fewer officials) on the field are each
tasked with a different set of responsibilities:[113]

 The referee is positioned behind and to the side of the offensive backs. The referee
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 is positioned in the defensive backfield, except in the NFL, where the
umpire is positioned lateral to the referee on the opposite side of the formation. 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 penalties. 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.

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.

 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 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 center judge is an eighth official used only in the top level of college football.
The center judge stands lateral to the referee, the same way the umpire does in the
NFL. The center judge is responsible for spotting the football after each play and
has many of the same responsibilities as the referee, except announcing penalties.
Another set of officials, the chain crew, are responsible for moving the chains. The
chains, consisting of two large sticks with a 10-yard-long chain between them, are used
to measure for a first down. The chain crew stays on the sidelines during the game, but
if requested by the officials they will briefly bring the chains on to the field to measure. A
typical chain crew will have at least three people—two members of the chain crew will
hold either of the two sticks, while a third will hold the down marker. The down marker, a
large stick with a dial on it, is flipped after each play to indicate the current down and is
typically moved to the approximate spot of the ball. The chain crew system has been
used for over 100 years and is considered to be an accurate measure of distance, rarely
subject to criticism from either side.[92]

Safety and brain health

See also: Protective equipment in gridiron football and Health issues in American
football

Vince Agnew wearing a helmet. Shoulder pads and thigh pads are visible under his uniform

Football is a full-contact sport, and injuries are relatively common. Most injuries occur
during training sessions, particularly ones that involve contact between players. [114] To try
to prevent injuries, players are required to wear a set of equipment. At a minimum
players must wear a football helmet and a set of shoulder pads, but individual leagues
may require additional padding such as thigh pads and guards, knee pads, chest
protectors, and mouthguards.[115][116][117] Most injuries occur in the lower extremities,
particularly in the knee, but a significant number also affect the upper extremities. The
most common types of injuries are strains, sprains, bruises, fractures, dislocations,
and concussions.[114]
Repeated concussions (and possibly sub-concussive head impacts[118]) can increase a
person's risk in later life for CTE (chronic traumatic encephalopathy) and mental health
issues such as dementia, Parkinson's disease, and depression.[119] Concussions are
often caused by helmet-to-helmet or upper-body contact between opposing players,
although helmets have prevented more serious injuries such as skull fractures.
[120]
 Various programs are aiming to reduce concussions by reducing the frequency of
helmet-to-helmet hits; USA Football's "Heads Up Football" program aims to reduce
concussions in youth football by teaching coaches and players about the signs of a
concussion, the proper way to wear football equipment and ensure it fits, and proper
tackling methods that avoid helmet-to-helmet contact. [121] However, a study in
the Orthopaedic Journal of Sports Medicine found that Heads Up Football was
ineffective; the same study noted that more extensive reforms implemented by Pop
Warner Little Scholars and its member teams were effective in significantly reducing
concussion rates.[122]
A 2018 study performed by the VA Boston Healthcare System and the Boston
University School of Medicine found that tackle football before age 12 was correlated
with earlier onset of symptoms of CTE, but not with symptom severity. More specifically,
each year a player played tackle football under age 12 predicted earlier onset of
cognitive, behavioral, and mood problems by an average of two and a half years. [123][124][125]

Leagues and tournaments

The National Football League (NFL) and the National Collegiate Athletic
Association (NCAA) are the most popular football leagues in the United States. [126] The
National Football League was founded in 1920 [127] and has since become the largest and
most popular sport in the United States.[128] The NFL has the highest average attendance
of any sporting league in the world, with an average attendance of 66,960 during
the 2011 NFL season.[129] The NFL championship game is called the Super Bowl, and is
among the biggest events in club sports worldwide. [130] 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.[131]
A high school football game during the first quarter

College football is the third-most popular sport in the United States, behind professional
baseball and professional football.[132] The NCAA, the largest collegiate organization, is
divided into three Divisions: Division I, Division II and Division III.[133] Division I football is
further divided into two subdivisions: the Football Bowl Subdivision (FBS) and
the Football Championship Subdivision (FCS).[134] The champions of each level of play
are determined through NCAA-sanctioned playoff systems; while the champion of
Division I-FBS was historically determined by various polls and ranking systems, the
subdivision adopted a four-team playoff system in 2014. [135]
High school football is the most popular sport in the United States played by boys; over
1.1 million boys participated in the sport from 2007 to 2008 according to a survey by
the National Federation of State High School Associations (NFHS). There is a stark
contrast in youth football participation between boys and girls. Only one youth football
league exists in the United States for girls, the GFL. The NFHS is the largest
organization for high school football, with member associations in all 50 states as well
as the District of Columbia. USA Football is the governing body for youth and amateur
football,[136] and Pop Warner Little Scholars is the largest organization for youth football.
[137]

Other professional leagues

Several professional football leagues have been formed outside the auspices of the
NFL.
Rival leagues
The most successful league to directly compete with the NFL was the American
Football League (AFL), which existed from 1960 to 1969. The AFL became a significant
rival in 1964 before signing a five-year, US$36 million television deal with NBC. AFL
teams began signing NFL players to contracts, and the league's popularity grew to
challenge that of the NFL. The two leagues merged in the 1970 season, and all the AFL
teams joined the NFL. An earlier league, the All-America Football Conference (AAFC),
was in play from 1946 to 1949. After it had dissolved, two AAFC teams, the Cleveland
Browns and the San Francisco 49ers, became members of the NFL; another member,
the Baltimore Colts joined the league, but folded after just a year in the NFL. [138]
Other attempts to start rival leagues since the AFL merged with the NFL in 1970 have
been far less successful, as professional football salaries and the NFL's television
contracts began to escalate out of the reach of competitors and the NFL covered more
of the larger cities. The World Football League (WFL) played for two seasons, in 1974
and 1975, but faced such severe monetary issues it could not pay its players. In its
second and final season the WFL attempted to establish a stable credit rating, but the
league disbanded before the season could be completed. [139] The United States Football
League (USFL) operated for three seasons from 1983 to 1985. 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. A subsequent
US$1.5 billion antitrust lawsuit against the NFL was successful in court, but the league
was awarded only $1 in damages, which was automatically tripled to $3 under antitrust
law.[140]
Complementary national leagues
The original XFL was created in 2001 by Vince McMahon and lasted for only one
season. Despite television contracts with NBC and UPN, and high expectations, the
XFL suffered from low quality of play and poor reception for its use of tawdry
professional wrestling gimmicks, which caused initially high ratings and attendance to
collapse.[141] The XFL was rebooted in 2020.[142] However, after only five weeks of play,
the league's operations slowly came to a close due to the ongoing COVID-19 pandemic,
[143]
 and filed for bankruptcy on April 13.[144] The United Football League (UFL) began
in 2009 but folded after suspending its 2012 season amid declining interest and lack of
major television coverage.[145] The Alliance of American Football lasted less than one
season, unable to keep investors.[146]
International play

Players with one of the youth divisions of the Borregos Salvajes football program of the Monterrey
Institute of Technology and Higher Education, Mexico City

American football leagues exist throughout the world, but the game has yet to achieve
the international success and popularity of baseball and basketball.[147] It is not
an Olympic sport, but it was a demonstration sport at the 1932 Summer Olympics.[1] At
the international level, Canada, Mexico, and Japan are considered to be second-tier,
while Austria, Germany, and France would rank among a third tier. These countries
rank far below the United States, which is dominant at the international level. [148]
NFL Europa, the developmental league of the NFL, operated from 1991 to 1992 and
then from 1995 to 2007. At the time of its closure, NFL Europa had five teams based in
Germany and one in the Netherlands. [149] In Germany, the German Football
League (GFL) has 16 teams and has operated for over 40 seasons, with the league's
championship game, the German Bowl, closing out each season. The league operates
in a promotion and relegation structure with German Football League 2 (GFL2), which
also has 16 teams.[150] The BIG6 European Football League functions as a continental
championship for Europe. The competition is contested between the top six European
teams.[150]
The United Kingdom also operated several teams within NFL Europe during the
League's tenure,[151] the resulting rise in popularity of the sport brought the NFL back to
the country in 2007 where they now hold the NFL International Series in London,
currently consisting of four regular season games.[152][153] 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[154][155][156]
An American football league system already exists within the UK, the BAFANL, which
has run under various guises since 1983. It currently has 70 teams operating across the
tiers of contact football in which teams aim to earn promotion to the Division above, with
the Premier Division teams competing to win the Britbowl, the annual British Football
Bowl game that has been played since 1985. [157][158][159] In 2007 the British Universities
American Football League was formed. From 2008, the BUAFL was officially associated
with the National Football League (NFL), through its partner organisation NFL UK.[160] In
2012, BUAFL's league and teams were absorbed into BUCS after American football
became an official BUCS sport.[161] Over the period 2007 to 2014, the BUAFL grew from
42 teams and 2,460 participants to 75 teams and over 4,100 people involved. [162]
American football federations are present in Africa, the
Americas, Asia, Europe and Oceania; a total of 64 national football federations exist as
of July 2012.[148] The International Federation of American Football (IFAF), an
international governing body composed of continental federations, runs tournaments
such as the IFAF World Championship, the IFAF Women's World Championship,
the IFAF U-19 World Championship and the Flag Football World Championship. The
IFAF also organizes the annual International Bowl game. [163] The IFAF has received
provisional recognition from the International Olympic Committee (IOC).[164] Several
major obstacles hinder the IFAF goal of achieving status as an Olympic sport. These
include the predominant participation of men in international play and the short three-
week Olympic schedule. Large team sizes are an additional difficulty, due to the
Olympics' set limit of 10,500 athletes and coaches. American football also has an issue
with a lack of global visibility. Nigel Melville, the CEO of USA Rugby, noted that
"American football is recognized globally as a sport, but it's not played globally." To
solve these concerns, major effort has been put into promoting flag football, a modified
version of American football, at the international level. [148]

Popularity and cultural influence

United States
Main article: American football in the United States
"Baseball is still called the national pastime, but football is by far the more popular sport
in American society", according to ESPN.com's Sean McAdam. [165] In a 2014 poll
conducted by Harris Interactive, professional football ranked as the most popular sport,
and college football ranked third behind only professional football and baseball; 46% of
participants ranked some form of the game as their favorite sport. Professional football
has ranked as the most popular sport in the poll since 1985, when it surpassed baseball
for the first time.[166] Professional football is most popular among those who live in the
eastern United States and rural areas, while college football is most popular in the
southern United States and among people with graduate and post-graduate degrees.
[167]
 Football is also the most-played sport by high school and college athletes in the
United States. In a 2012 study, the NCAA estimated there were around 1.1 million high
school football players and nearly 70,000 college football players in the United States; in
comparison, the second-most played sport, basketball, had around 1 million participants
in high school and 34,000 in college.[168] The Super Bowl is the most popular single-day
sporting event in the United States,[31] and is among the biggest club sporting events in
the world in terms of TV viewership.[130] The NFL makes approximately $10 billion
annually.[169] Super Bowl games account for seven of the top eight most-watched
broadcasts in American history; Super Bowl XLIX, played on February 1, 2015, was
watched by a record 114.4 million Americans.[170]

The Boise State Broncos are the first football team to design a blue field in 1986

American football also plays a significant role in American culture. The day on which the
Super Bowl is held is considered a de facto national holiday,[171] and in parts of the
country like Texas, the sport has been compared to a religion. [172][173] Football is also
linked to other holidays; New Year's Day is traditionally the date for several college
football bowl games, including the Rose Bowl. However, if New Year's Day is on a
Sunday, the bowl games are moved to another date so as not to conflict with the typical
NFL Sunday schedule.[174] Thanksgiving football is an American tradition,[175] hosting
many high school, college, and professional games. [176] Steve Deace of USA
Today wrote that Americans are passionate about football "because it embodies
everything we love about American exceptionalism. Merit is rewarded, not punished.
Masculinity is celebrated, not feminized. People of various beliefs and backgrounds – a
melting pot, if you will – must unify for a common goal for the team to be successful".
[177]
 Implicit rules such as playing through pain and sacrificing for the better of the team
are promoted in football culture.[178]
The safety of the sport has also sparked national controversy in American popular
culture. It is often received as "overly aggressive", and defamiliarized in popular culture.
[179]
 The 2015 film Concussion aimed to shed light on the sport's safety, specifically in the
NFL by having Will Smith portray Dr. Bennet Omalu, a neuropathologist who was the
first to discover and publish findings of chronic traumatic encephalopathy or CTE.
Other countries
In Canada, the game has a significant following. According to a 2013 poll, 21% of
respondents said they followed the NFL "very closely" or "fairly closely", making it the
third-most followed league behind the National Hockey League (NHL) and Canadian
Football League (CFL).[180] American football also has a long history in Mexico, which
was introduced to the sport in 1896. It was the second-most popular sport in Mexico in
the 1950s, with the game being particularly popular in colleges. [181] The Los Angeles
Times notes the NFL claims over 16 million fans in Mexico, which places the country
third behind the U.S. and Canada.[182] American football is played in Mexico both
professionally and as part of the college sports system. [183] A professional league,
the Liga de Fútbol Americano Profesional (LFA), was founded in 2016.[184]

Opening ceremony of the 2010 NFL International Series at London's Wembley Stadium

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. Play
was halted during World War II, but the sport began growing in popularity again after the
war. As of 2010, there are more than 400 high school football teams in Japan, with over
15,000 participants, and over 100 teams play in the Kantoh Collegiate Football
Association (KCFA).[185] The college champion plays the champion of the X-League (a
semi-professional league where teams are financed by corporations) in the Rice Bowl to
determine Japan's national champion.[186]

A 2012 football match between national teams of Finland and Sweden at the Sonera Stadium (now

Bolt Arena) in Helsinki, Finland

Europe is a major target for the expansion of the game by football organizers. In the
United Kingdom in the 1980s, the sport was popular, with the 1986 Super Bowl being
watched by over four million people (about 1 out of every 14 Britons). Its popularity
faded during the 1990s, coinciding with the establishment of the Premier League—top
level of the English football league system. According to BBC America, there is a "social
stigma" surrounding American football in the UK, with many Brits feeling the sport has
no right to call itself "football" due to the lack of emphasis on kicking. [187] Nonetheless,
the sport has retained a following in the United Kingdom; the NFL operates a media
network in the country, and since 2007 has hosted the NFL International Series in
London. Super Bowl viewership has also rebounded, with over 4.4 million Britons
watching Super Bowl XLVI.[188] The sport is played in European countries like
Switzerland, which has American football clubs in every major city, [189] and Germany,
where the sport has around 45,000 registered amateur players. [183]
In Brazil, football is a growing sport. It was generally unknown there until the 1980s
when a small group of players began playing on Copacabana Beach in Rio de Janeiro.
The sport grew gradually with 700 amateur players registering within 20 years. Games
were played on the beach with modified rules and without the traditional football
equipment due to its lack of availability in Brazil. Eventually, a tournament, the Carioca
championship, was founded, with the championship Carioca Bowl played to determine a
league champion. The country saw its first full-pad game of football in October 2008.
[190]
 According to The Rio Times, the sport is one of the fastest-growing sports in Brazil
and is almost as commonly played as soccer on the beaches of Copacabana
and Botafogo.[191]
Football in Brazil is governed by the Confederação Brasileira de Futebol
Americano (CBFA), which had over 5,000 registered players as of November 2013. The
sport's increase in popularity has been attributed to games aired on ESPN, which began
airing in Brazil in 1992 with Portuguese commentary. [192] The popularity and "easy
accessibility" of non-contact versions of the sport in Brazil has led to a rise in
participation by female players.[191] According to ESPN, the American football audience in
Brazil increased 800% between 2013 and 2016. The network, along with Esporte
Interativo, airs games there on cable television. Football is often associated in Brazil as
being the sport of supermodel Gisele Bündchen's husband Tom Brady. 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.[193]

Variations and related sports

See also: Canadian football, Arena football, and Flag football
Men playing a game of flag football

Canadian football, the predominant form of football in Canada, is closely related to

American football—both sports developed from rugby and are considered to be the
chief variants of gridiron football.[194] 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),[195] teams have three downs instead of four,
there are twelve players on each side instead of eleven, [196] 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.[197] The Canadian Football League (CFL) is the major Canadian
league and is the second-most popular sporting league in Canada, behind the National
Hockey League.[197] The NFL and CFL had a formal working relationship from 1997 to
2006.[198] The CFL has a strategic partnership with two American football leagues, the
German Football League (GFL) and the Liga de Futbol Americano Profesional (LFA).
[199]
 The Canadian rules were developed separately from the American game.
Indoor football leagues constitute what The New York Times writer Mike Tanier
described as the "most minor of minor leagues." Leagues are unstable, with franchises
regularly moving from one league to another or merging with other teams, and teams or
entire leagues dissolving completely; games are only attended by a small number of
fans, and most players are semi-professional athletes. The Indoor Football League is an
example of a prominent indoor league. [200] The Arena Football League, which was
founded in 1987 and ceased operations in 2019, was one of the longest-lived indoor
football leagues.[201] In 2004, the league was called "America's fifth major sport" by ESPN
The Magazine.[202]
There are several non-contact variants of football like Flag football.[203] In flag football the
ballcarrier is not tackled; instead, defenders aim to pull a flag tied around their waist.
[204]
 Another variant, touch football, simply requires the ballcarrier to be touched to be
considered downed. Depending on the rules used, a game of touch football may require
the player be touched with either one or two hands to be considered down. [205]