How to Play American Football
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American football is a full contact game between two teams. Each team has 11 players on the field at any given time. The goal of the offense is to move the ball to the other end of the field to score. The goal of the defense is to stop the offense.
American football is a full contact sport where the offense can advance the ball until the ball-carrier is tackled.
The game is 60-minutes long, and is commonly broken into four 15-minute long periods known as “quarters”.
A play starts when the offense “snaps” the ball—where one player on offense called the “Center” hands or passes the ball backwards to begin the play. The play lasts until the offense scores, or the ball-carrier is tackled by the defense. Once the play ends, the ball is dead and there is no action until the next snap.
Typically, each team is allowed to stop the clock and call three “timeouts” per half.
The basic rules of American football focus on player safety and fairness of competition. Here are all the rules that apply to offenses, defenses, special teams, and other general rules for player safety and the image of the game.
Rules for the Offense
The offense starts every play by snapping the ball. This occurs when the “Center” position gives the ball to the “Quarterback,” or another offensive player who is positioned behind the Center. The offense typically has 40-seconds to snap the ball in between each play. This is tracked via the “play clock.” The 40-second play clock is utilized in both college and professional football.
False start penalty
The offense must all start at the same time. If they fail to do so, a “False Start” penalty is called. This costs the offense 5 yards.
Delay of Game
If the offense fails to snap the ball before the 40-second play clock runs out, they have committed a “delay of game” penalty. This costs the offense 5 yards.
Illegal formation penalty
The offense must have seven players positioned on the “line of scrimmage”—the line where the ball is spotted—to legally begin a play. If there are not seven players on the line of scrimmage, an illegal formation flag is thrown.
The penalty for illegal formation is typically 5 yards. Though, there may be a 10-second runoff if the penalty occurs with less than two minutes left in the game.
A shift is when more than one player on offense moves before the snap. Shifts are allowed, so long as the formation follows the rules and all offensive players are set for at least 1 second before the ball is snapped.
If the offensive players who shifted are not set for 1 or more seconds prior to the snap, an illegal shift flag is thrown. The penalty for an illegal shift is 5 yards.
A motion is when one offensive player is moving before the snap. A flag for illegal motion occurs when the offense sends a player in motion towards the line of scrimmage. In college football and the NFL, offensive players are forbidden from getting a running start before the ball is snapped. The penalty for this flag is 5 yards against the offense.
Illegal Forward Pass
Forward passes are allowed if the offensive player throwing the ball, often the “Quarterback,” is behind the line of scrimmage, and there has not already been another forward pass thrown on that play. A forward pass outside of these rules is illegal, and costs the offense 5 yards. In the NFL, this is accompanied by a loss of down.
Ineligible Player Downfield on a Pass
An “Ineligible Player Downfield” flag is thrown when an offensive player, who is not eligible to catch a pass, is caught more than 3-5 yards downfield (depending on specific rules in college and the NFL) when a pass is thrown. Ineligible players are most commonly offensive linemen. The penalty is 5 yards.
Intentional grounding occurs when a Quarterback throws the ball away, without a realistic chance for completion. The NFL defines “realistic chance for completion” as:
“A pass that is thrown in the direction of and lands in the vicinity of an originally eligible receiver”
For intentional grounding to be called, the Quarterback’s pass must either: not have made it back to the line of scrimmage, or, if the Quarterback is still in the pocket, not be in the vicinity of an originally eligible receiver. If the Quarterback is outside of the pocket, the ball does not have to have a “realistic chance for completion,” so long as the pass made it past the original line of scrimmage.
The penalty for intentional grounding is multifold. A loss of down occurs, the ball is either placed at the spot of the foul or the offense is assessed a 10 yard loss, or, if the penalty occurs in the offense’s own endzone, a safety is called and the defense is awarded 2 points.
Generally speaking, a chop block occurs when one offensive player blocks a defender low, while another offensive player blocks that same defender, at the same time, high. Since this creates a dangerous situation for the defensive player, the penalty for a chop block flag is 15 yards against the offense.
Clipping is a flag that occurs when one player comes from behind and charges or falls on the lower body of another player. Clipping is illegal due to the likelihood of injury from such an action unless the player that is “clipped” is the ball carrier. The penalty for a clipping flag is 15 yards, and an automatic first down is called against the defense.
Offensive Pass Interference
Offensive pass interference occurs when an eligible receiver significantly hinders a defensive player’s opportunity to intercept the ball, when the action occurs more than 1 yard beyond the line of scrimmage. Most commonly, offensive pass interference is called when the eligible receiver pushes-off the defensive player to catch a pass.
The penalty for offensive pass interference is 10 yards from the previous spot of the ball.
Rules for the Defense
A flag for defensive offsides is thrown when a defender crosses the line of scrimmage before the ball is snapped. A defensive player is allowed to move freely before the snap, unlike offensive players, and can even cross the line of scrimmage as long as they are back onsides before the ball is snapped.
The penalty for a defensive offsides flag is 5 yards.
Encroachment is when a defensive player moves offsides and makes contact with a player on the offense. Encroachment can only be called before a play starts. The penalty for encroachment is 5 yards.
Neutral Zone Infraction
A neutral zone infraction is when a defensive player moves offsides and causes an offensive player to commit a false start. The “neutral zone” is essentially the line of scrimmage; it is the space, the length of the football, where the ball is placed between snaps.
Defensive players are allowed to move freely before the snap. They can even go offsides as long as they are back onsides before the plays begins. However, if their movement offsides forces an offensive player to react and commit a false start penalty—then the defense is guilty of a neutral zone infraction.
A neutral zone infraction is a 5 yard penalty.
Illegal Contact by the Defense
Defensive illegal contact occurs when a defender makes contact with an offensive player beyond 5 yards from the line of scrimmage.
A defensive player is allowed to “chuck” (make contact) with a player on offense as long as:
- The offensive player is within 5 yards, and
- The offensive player has not moved “beyond a point that is even with the defender,” and
- The defender does not make contact with the back of the offensive player.
The penalty for illegal contact by the defense is 5 yards and an automatic first down for the offense.
A flag for defensive holding is thrown anytime a player on defense tackles or grabs an offensive player that does not have the ball. It is most commonly called on defensive players who are covering wide receivers, or other pass catchers, on the offense.
The penalty for defensive holding is 5 yards and an automatic first down in the NFL. In college, defensive holding costs 10 yards and an automatic first down.
Defensive Pass Interference
Defensive pass interference occurs when a defender significantly hinders an offensive player’s opportunity to catch a pass, when the action occurs more than 1 yard beyond the line of scrimmage.
Rules for defensive pass interference apply from the time the ball is thrown until the ball is touched.
The penalty for defensive pass interference is a first down for the offense and the ball at the spot of the foul. This can be a devastating penalty for a defense, and a game-changing opportunity for the offense.
Rules for Player Safety
A horse collar penalty is called for horse collar tackles. A horse collar tackle is when a defensive player grabs the inside of the back, or side, of the ball carrier’s shoulder pads and pulls them to the ground. Grabbing the ball carrier’s jersey at or above the nameplate and pulling them to the ground is considered a horse collar tackle, as well.
Horse collar tackles are legal in some cases—for instance, when a Quarterback is in the pocket or a ball carrier is within the tackle box.
The penalty for a horse collar tackle is 15 yards and an automatic first down.
Use of the Helmet
In the NFL, it is a flag for any player to lower their head to initiate contact with their helmet against an opponent. The intent of the rule is to eliminate dangerous helmet to helmet collisions.
Contact does not have to be to an opponent’s head or neck area. Any instance of a player lowering their helmet to make contact with another player is a flag for use of the helmet.
The penalty for use of the helmet is 15 yards. If it is called against the defense, the penalty is 15 yards and an automatic first down for the offense. Players may be ejected for use of the helmet based on stricter standards.
Targeting is a flag in college football when any player takes aim at an opponent to make forcible contact that goes beyond making a legal tackle or block. It is most commonly applied when a player initiates contact with their helmet.
The purpose of targeting is to reduce the instance of dangerous hits to the head.
The penalty for targeting is severe—the guilty player is ejected from the game, and their team is assessed 15 yards. All targeting flags are reviewed by video evidence before the ejection is confirmed. The targeting rule in college football has been controversial since its inception due to the severity of the penalty.
Face mask is a penalty for any twisting, turning, or pulling of an opponent’s face mask. The purpose of the face mask flag is to protect players from head injuries.
The penalty for a face mask flag is 15 yards. It is also an automatic first down if the flag is committed by the defense.
Personal foul is a broad terms that covers many different types of illegal plays in football. A personal foul is an umbrella penalty for any unnecessary or cheap play.
Some examples of personal fouls include: unsportsmanlike conduct (with contact), roughing the passer, roughing the kicker, hit to a defenseless receiver, and more.
The penalty for a personal foul is severe. Typically they are 15 yards penalties that include an automatic first down if it’s committed by the defense.
Tripping is when a player intentionally trips another player. It can be called on either an offensive or defensive player. T
he penalty for tripping is 10 yards. If tripping is called on the defense, then the offense also receives an automatic first down.
Illegal substitution & Too Many Men on the Field
An illegal substitution, or “Too Many Men on the Field,” penalty occurs when either the offense or defense makes a substitution that results in there being more than 11 players on the field for their team. The cost of this penalty is 5 yards.
Illegal Use of the Hands
A penalty for “Illegal Use of the Hands” occurs when a player intentionally hits another player in the face / head region with their hands. It can be called against offensive or defensive players. The cost for an “Illegal Use of the Hands” penalty is 10 yards if it is called on the offense. The cost if it is called on the defense is 5 yards and an automatic first down for the opposing offense.
Illegal Block in the Back
An illegal block in the back is called when the offense or receiving team blocks a defensive player in their back and above their waist.
The penalty for an illegal block in the back is 10 yards.
Unnecessary roughness is a flag when unnecessary contact is made against a player in a defenseless posture.
The penalty for unnecessary roughness is 15 yards and an automatic first down. A player may be ejected for an egregious unnecessary roughness penalty.
Rules for Special Teams
Roughing the Kicker
A flag for roughing the kicker is called when a player makes contact with a kicker:
- In the kicker’s plant leg while their kicking leg is still in the air, or
- Slides into the kicker or makes severe contact with the kicker when the kicker’s feet are both on the ground.
Roughing the kicker is considered a severe flag. The penalty for roughing the kicker is 15 yards and an automatic first down.
Running into the Kicker
Running into the kicker occurs when a defensive player contacts the kicking foot of the kicker or slides under the kicker, preventing them from returning to the ground while in their kicking motion.
The penalty for roughing the kicker is 5 yards.
Ineligible Player Downfield on a Kick
On a punt, no player except for the two furthest outside—commonly referred to as the “gunners”—are allowed to move past the line of scrimmage until the ball is kicked.
The cost of an ineligible player downfield on a kick penalty is 5 yards.
Invalid Fair Catch Signal
A “fair catch” is allowed when the ball is kicked, either during a punt or Kick Off. It is a rule designed to protect the kick returner.
A kick returner signals for a fair catch by raising one hand above their shoulder and waving their arm back and forth, while the ball is in the air. This indicates a “fair catch,” which means they cannot be tackled. On a punt, a “fair catch” means that the ball will be placed at the spot where the ball is caught. On a Kick Off, a “fair catch” places the ball at the 25 yardline, just like a touchback.
Any other manner of motion by a returner is considered an “Invalid Fair Catch Signal.” The penalty is 5 yards from the spot of the foul.
Kicking Team Player Voluntarily Out of Bounds
If a player on the kicking team runs out of bounds voluntarily, or if they are pushed out of bounds and do not immediately re-establish themselves in bounds, it is a 5 yards penalty.
This is to prevent a kicking team player from being able to run down field unobstructed and have a clearer path to tackle the kick returner.
A flag for unsportsmanlike conduct penalty costs 15 yards. Taunting is an example of an unsportsmanlike conduct penalty. Unsportsmanlike conduct is an umbrella penalty that includes any behavior or actions that are generally accepted as outside of the good faith of the sports, or with the intent to cause unnecessary strife with an opponent.