play in American football consists of a series of individual
plays of short duration, outside of which the ball is not in play.
These plays are often referred to as "downs." Unlimited
substitutions can be made between plays.
Object of the game
The object of the game is to advance the ball to the opponent's
end zone and thus score points. The team with the most points
when time has expired wins.
Methods of scoring
Points can be scored in the following ways:
1.) A field goal, worth 3 points, is scored by kicking the ball
between the uprights of the goal posts. In the NFL Europe league,
Field Goals over 50 yards attract 4 points.
2.) A touchdown, worth 6 points, is scored when the ball is advanced
into the opponent's end zone. Immediately after a touchdown, the
scoring team may run a single play called a try (more commonly
called an extra point or conversion attempt) from just outside
the end zone. They can either attempt to kick the ball through
the uprights (worth one point, for a total of seven) or advance
the ball into the end zone (worth 2, for a total of eight) on this
A safety is a rare event occurring when a player causes the ball
to become dead in his own end zone. When this occurs, the opposing
team scores 2 points and gains posession. Typically this occurs
when a ballcarrier is tackled in their own endzone, or fumbles
the ball out of their own endzone.
Duration of game
Collegiate and professional football games are 60 minutes long,
divided into four quarters of 15 minutes each. Separating the
second and third quarters is a halftime. If a game is tied at
the end of four quarters, overtime is played. Professional overtime
is played in 15-minute "sudden death" periods, meaning
that the team that scores first, by any means, wins. In college
football, a shootout style overtime system ensures that each
team has equal opportunity to score. Some High School games play
12-minute quarters instead of 15.
A kickoff starts each half, and also restarts play following a
field goal or touchdown. At the beginning of a half, the kicking
team is determined by coin toss. After a team scores a field
goal or touchdown, it kicks off the ball to its opponent. The
ball is placed on a tee and kicked off at the kicking team's
own 30-yard line in the NFL, or its own 35-yard line in college
football. The ball is usually kicked as far as possible down
the field, but sometimes a team will attempt to recover its own
short kick, in a play known as an onside kick. The receiving
team may catch and attempt to advance the ball at any time after
the kick, but the kicking team may not touch the ball until it
has traveled at least 10 yards.
Following a safety, a free kick similar to a kickoff is used to
restart the game. The team that was scored upon kicks the ball
from its own 20-yard line. In this case, a tee cannot be used,
so the ball is usually punted.
In the NFL, a team's coach may "challenge" a play if
he thinks an official's ruling is incorrect.
He does so by tossing a red flag (like the yellow flags used by
officials to denote
penalties) onto the field. The official that made the call then
has 90 seconds
to review multiple videotaped angles of the play, and then he either
overturns or upholds the ruling. If the ruling is upheld, the team
that challenged the play is charged with a time out. A team may
usually challenge only two plays per game. However, if a team is
successful on two challenges in a game, they will receive a third
challenge. A play can only be challenged before the next one has
The officials may decide to review a play themselves
if they do not all agree on the call. No team is charged with
in this event. Only officials can review plays in the last two
minutes ("two-minute warning") of each half or in overtime
periods. This system was introduced in 1999.
Plays of the game
A game consists of many individual plays. The vast majority of
these are scrimmage plays.
Each play from scrimmage is one of a series of downs given to
the team with possession.
These two concepts, the concept of scrimmage, and the concept
are fundamental to American football, and are what distinguish
it, as well as Canadian football, from most other forms of football.
However, rugby league does have a similar system where each side
is allowed to be tackled six times while in possession before
surrendering possession (see the entry for rugby league for an
explanation of the play-the-ball and the limited tackles rule).
The team with possession of the ball is called
the offensive team, and the other team the defensive team.
A set of downs begins
a first down, which is given to a team either after it has just
gained possession on the previous play, or it has gained the necessary
yardage from a previous set of downs. On a first down, the offensive
team is given four downs to gain 10 yards. This is commonly referred
to as "first and ten", meaning that it is first down,
and ten yards are needed to get another first down. The line a
team must reach in order to gain a first down is technically called
the line to gain or the necessary line, although it is commonly
called the first down line. In the event a team gains a first down
and the new line of scrimmage is within ten yars of their opponent's
goal line, the goal line becomes line to gain. This is commonly
known as "first and goal," signifying that no more first
downs can be achieved, and it is necessary to score on the current
set of downs. Failure to gain the necessary yardage on a set of
downs results in a "turnover on downs."
Plays from Scrimmage
Each down is a play from scrimmage. Prior to each play from scrimmage,
the two teams line up on opposite sides of a line of scrimmage,
which is defined by the spot of the ball from the previous play.
The spot is, in most cases, the yard line at which the ball became
dead on the previous play, plus or minus any penalty yardage.
A down, or play from scrimmage, begins with a snap and ends when
the ball becomes dead for any reason. In a snap, the center either
hands the ball between his legs to the quarterback, or tosses
it backwards between his legs to the quarterback or sometimes
another player, such as a punter or a holder for a field goal
attempt. The ball may become dead, ending the down, because a
player in possession is tackled, or because his forward progress
is stopped, or because he goes out of bounds, or because a forward
pass goes incomplete, or because a player makes a "fair
catch" (see punts below). Each play from scrimmage can be
either an attempt to advance the ball, a punt, or an attempt
a field goal.
Advancing the ball
There are two methods of advancing the ball while still maintaining
1.) Running the ball - The quarterback, who normally receives
the snap, either hands the ball or throws a lateral pass to a running
back, who then becomes the ball carrier. Most other players on
the offense have blocking assignments, and attempt to prevent the
defense from tackling the ball carrier. The quarterback may also
run the ball himself.
2.) A forward pass - A forward pass may only
be thrown on a play from scrimmage, and only from behind the
line of scrimmage.
must be thrown to an eligible receiver (any player who is not an
interior lineman). A completed pass is one caught by a member of
the offense, although if the first player to touch the ball is
not an eligible receiver, a penalty results. The player may run
with the ball after catching it. To be considered "in bounds" a
receiver must have clear possession of the ball and place both
feet (NFL) or one foot (college) in bounds prior to stepping out
of bounds. An incomplete pass is any forward pass that either hits
the ground or goes out of bounds, at which point the ball becomes
dead, and is spotted at the preceding line of scrimmage for the
following play. An interception a pass caught by the defense, which
transfers possession to the defending team.
It is important for the offense to run a variety of running and
passing plays in order to keep the defense uncertain of the next
Fourth down situations
If a team uses all four of its downs without gaining the yardage
for a first down or a touchdown, and without kicking a field
goal, possession shifts to the other team. This is called turning
the ball over "on downs." Fourth down situations are
therefore pivotal. The offense has the same three choices as
on any other play from scrimmage: advance the ball, punt, or
attempt a field goal — but the decision is often more difficult
Offensive options on fourth down:
1.) "Go for it" - despite the risk involved, a team
may always elect to "go for it" on fourth down by making
one last attempt to reach the first down marker or the goal line,
mounting a regular running or passing play to get there (just as
they did on the first three downs). This is most common when, due
to a team's success on the first three downs, the distance required
for a first down is short; or when it is trailing late in the game
by more than three points (the value of a field goal). The risk
is significant: failing to make the next first down or score gives
possession of the ball to the opposing team, usually with better
field position than would have resulted from a kick. It's often
wise to kick on fourth down.
2.) Punt - If the team thinks it is too far away to attempt a
field goal, it may punt the ball to the other team in order to
gain better field position.
3.) Attempt a field goal - Field goal attempts
must be made with the ball on the ground (they cannot be punted),
so a player
a holder holds the ball for a kicker. In times past, a kicker might
have tried a "drop kick" — that is, dropping the
ball and kicking it after it bounces off the ground — and
if the kicker kicks it through the goalposts, it is a field goal.
This is difficult to do, as the ball is in the shape of a prolate
spheroid and its bounce is unpredictable. Nowadays, the only time
you will see this is by a hurried kicker after a broken play. Failed
field goal attempts, if they are short, can be returned by the
opponent, but the ball usually goes past the end line and can't
be returned. If the field goal attempt fails, the ball is spotted
at the original line of scrimmage, and possession is given to the
other team. (In the NFL, failed field goal attempts are spotted
at the spot of the kick or the 20, whichever is farther from the
goal line.) Field goals can also be attempted on other downs, but
this is only seen in situations where a field goal will either
win or tie the game and the distance to kick the field goal is
well within range of the kicker.
A team will occasionally run a trick play on fourth down. They
will line up in a punting or field goal formation, but will instead
run the ball or pass it in an attempt to pick up a first down.
Specialized units and players
With its unlimited substitutions, American football is highly specialized,
with most teams having three specialized units: an offensive
unit, a defensive unit, and special teams.
There are many specialized players within each unit. Some players
may only be used in certain situations. (for details see: offensive
unit, defensive unit, special teams, linemen, defensive schemes.)
A list of player types and definitions can also be found in the
Glossary of American football.