Rules of American football game

American football matches are played between two teams, with a maximum of 53 players (NFL rules). Both teams sent 1 1 players to play, and some or all players can be replaced at any time.

The man who gets the ball is the attacker. The goal is to push the ball as far as possible to the opponent's position and try to cross the scoring line and enter the opponent's end zone to score. There are two ways to attack, the player takes the ball forward (rushing) or throws the ball forward (passing). The defender's goal is to prevent the opponent from scoring as much as possible and force the opponent to lose possession of the ball. If the attacker scores successfully or loses possession of the ball, the two teams exchange offense and defense, and the game will continue in turn until the end of the fourth quarter. The early American football was basically rugby.1After the reform in the late 9th century, its size was reduced and its shape changed. At present, American football is about111.25 inch (27.94 ~ 28.58 cm), and the center circumference of the ball is about 2 1 ~ 2 1.25 inch (53.35 inch). Although its sphere is olive-shaped, it is not closer to the standard oval shape like football, but its two ends are slightly pointed in the shape of "vesica piscis", which is the most efficient shape for one-handed forward throwing and long pass. Similar Canadian football (also known as Canadian football) looks closer to rugby in appearance and slightly different from American football in size, but the balls used in both sports can be used in most cases. Each football consists of four pieces of leather (or plastic), and each piece of leather has to go through a series of heavy and cracked quality inspections before the workers officially start the production process. Two of them are punched at the connection edge and tied together with ropes. One of the tied leather blocks passes through two rows of holes to reinforce the center and fix the inflatable piston. Part or all of the structural leather blocks of the sphere will bear the manufacturer's brand, competition or alliance name, signature or other imprint. Each piece of leather has an inner lining, and the four pieces of leather are sewn back, but there is no need to sew where there are rope holes. The leather shell is turned inside out through this crack. Finally, an airbag made of polyurethane or rubber and weighing about 65,438+02.5 ~ 65,438+03.5 ounces (354.37 ~ 382.72 grams) is inserted through the crack, and then PVC or thong is tied along the hole. Before use, the rubber ball should be inflated to the air pressure of12.5 ~13.5 psi (86.2 ~ 93.1kpa).

Ball shells used in NFL professional competitions or NCAA university competitions must be made of real leather and dyed brown in natural leather, while amateur entertainment balls are sometimes made of rubber or plastic. Modern tanning technology can press pebbles on the leather surface to increase friction, so that rubber balls will not slip and get rid of them in dry or wet environment. In American football, white semi-circular stripes (two pieces of leather on both sides of the seam) are usually painted on both ends of the ball to increase the eye-catching degree in low light, but NFL balls do not have white stripes. Because the early American football was made of inflatable pig bladder, it was also commonly known as "pig skin".

According to NFL official regulations, the home team should prepare 36 balls for outdoor games and 24 balls for indoor games two hours before the start of the game, so that the ball cards can be measured by barometer, which is in line with league regulations. Twelve brand-new footballs, sealed in a special box and delivered by the manufacturer, were unsealed by football cards in the locker room two hours before the start of the game. These footballs need to be specially stamped with the English letter "K" for football matches. The stadium of American football is often nicknamed Gridiron, because the pattern of vertical and horizontal lines on the stadium makes it look like a wire rack that can help food barbecue on the stove. For this reason, American football and similar Canadian football are collectively called "gridiron football". Because American football is more representative between the two, other English-speaking countries even use "gridiron" to refer to American football. The standard court used by NFL and NCAA is a rectangular lawn, with a length of 360 feet (120 yards or 109.7 meters) and a width of 160 feet (53.33 yards or 48.8 meters) (some indoor competitions will use grass-like carpets). The longer boundary is called the edge line, and the shorter boundary is called the end line. The marker line before the finish line is called the goal line. There is an area with a depth of 65,438+00 yards (9.65,438+0 meters) between the end line and the goal line on both sides of the court, which is called the end line area (also called the touchdown area). At each corner of the end zone, there is an orange rectangular column (tower) about 65,438+0 feet long. The score lines on both sides are 100 yards (9 1.44 meters) apart, and the area between them is also the competition venue. Draw a bar code line every 5 yards (4.6 meters) from the scoring line in the competition area, and draw a number every 10 yards until the 50-yard line reaches the middle of the midfield. In the middle and both sides of the court, short horizontal marking lines are arranged parallel to the sideline, called hash lines, and the code lines near the sideline are called boundary lines. Any player must serve on or off the court.

According to NFL rules, the range within the boundary of the stadium does not include the sideline and the end line itself. If the ball is above the sideline or end line, it is out of bounds. The score line is considered as a part of the end line. If the ball is above the scoring line and the attacker holds the ball, it is considered a successful touchdown.

Two doorposts (also called uprights) with an interval of 65,438+08.5 feet (5.64 meters) stand in the center of the terminal area, and are connected by a crossbar, which is 65,438+00 feet (3.048 meters) from the ground. The ball must pass between two goalposts and the crossbar to be a successful shot. In some low-level competitions, the goalposts are sometimes widened to 23.33 feet (7. 1 1 m) to increase the success rate of shooting. American football is a contact sport with fierce confrontation. Due to the violent collision common in the game, players must wear armor-like protective gear. These protective devices mainly include helmets with cage masks, upper body armor with shoulder pads and chest protectors. In addition, according to the league level, they will also include tooth protectors, gloves and pads covering elbows, waist, hips, hips, thighs and knees.

According to statistics, the use of protective gear can reduce the probability of serious injuries by more than half. Nevertheless, the fierce nature of American football still makes injuries inevitable. Among them, concussion caused by blunt force of physical impact is particularly common, and tens of thousands of players are injured every year. The standard American football game is divided into four sections, each section 15 minutes. The first and second quarters are called the first half of the year, and the third and fourth quarters are called the second half. There is a half-time break of 12 minutes in the first and second half (20 minutes in college games). At the beginning of the second half, the kick-off meeting will be the same as at the beginning of the game. The first quarter of the first half is over, and the third quarter of the second half is over. Each player has a two-minute break, and the players of both sides exchange venues. The original owner of the ball will continue to attack after changing venues.

After each attack, the attacker must restart the next attack within 40 seconds, or he will be punished. In addition to exchanging possession of the ball, the timing of the game is suspended in the following situations: the ball fails, the player takes the ball out of bounds, the referee whistles for a foul, and the coach asks for a timeout (only three times). When the referee put the ball back to the kick-off point for both sides to start attacking, the game clock began to tick.

extra time

If the two sides draw at the end of the four normal quarters, there will be 15 minutes of overtime after the 3-minute break, and each side will have one chance to control the ball and two pauses. At the beginning of overtime, both sides toss a coin to guess first, and the right one can choose to attack or defend first. Usually in the NFL regular season, if the scores of both sides are still tied after the first overtime, the normal game will end in a draw. In the playoffs, because it is a knockout, there must be a winner, so the winner will be decided according to the sudden death method, and the team that scores first wins the game. One drawback of this rule is that the winner of the guessing game often chooses to get possession of the ball, and then pushes the front line closer to win overtime by scoring, while the other side has little chance to get possession of the ball to recover the score. In the 20 10 season, the NFL revised the rules, stipulating that no matter which side must score a touchdown, it will cause sudden death. If it is a goal, the opponent can still control the ball and have a chance to overtake.

The game between college and high school adopts the Kansas playoffs, that is, no matter how the first attacker scores, the other side will still take turns to control the ball and have the opportunity to recover the score. If the first quarter is still tied after overtime, add the second quarter, if the second quarter is still tied, add the third quarter ... until the winner of the game is produced. However, after the third quarter, the team that scored a touchdown needs to convert 2 points to get extra points (see "scoring method" below). The game started with a kick-off. The defender's kicker puts the ball on his tee on the 30-yard line and kicks it to the attacker. After receiving the ball, the attacker's backhand will try to push forward until it is intercepted by the defender. Then the attacker attacks from where the ball is intercepted.

If the attacker catches the opponent's kick-off in his own end zone, he has two choices: either rush out of the end zone with the ball and go to the opponent's site run until he is intercepted; Either touch the ground with your knees after holding the ball, that is, stop the ball, and then put the ball on the attacker's 20-yard line, and the attacker begins the first round of attack. American football adopts the way of round competition, and the attack mode is similar to six-a-side football and league football. The attacker has four opportunities to advance 10 yards (the end zone of the defender), and each opportunity is called a "down" attack (that is, an opportunity to be intercepted by the other side). When the attacker successfully pushes more than 10 code in the fourth attack, he can get a new fourth attack opportunity, which is called getting a new "first gear" (1st down, also known as the first attack). By constantly gaining a new first attack, the attacker can carry out a series of continuous attacks and keep moving forward until he scores. The defender's goal is also simple-try to prevent the opponent from advancing enough distance in the fourth attack and force them to exchange possession.

If the attacker can't achieve the tactical goal of advancing 10 yards in the fourth attack, he should hand over the ball to the opponent at the end of the fourth attack. Under normal circumstances, if the attacker is still not sure to advance enough distance when launching the fourth attack, most of them will pass the ball to the opponent in the form of a gondola.

Except for the kick-off at the beginning, half-time and after scoring, every attack must start with the same attack: the offensive and defensive sides are arranged on both sides of the offensive and defensive line, facing each other. The attacking center reaches into the neutral zone with one hand to hold the ball, and then passes it back to his teammates from between his legs. The teammate who catches the ball is usually the quarterback of the attacking team, but under special circumstances, it may also be other teammates (such as Rotarians of the Secret Service). No one is allowed to cross the offensive and defensive line before the center serves, or he will be fined. From the moment of serving, the game officially resumed, and both sides continued to compete for possession and scoring opportunities.

There are two main ways for the attacker to move forward:

1. After receiving the service from the center, the quarterback takes the ball by himself or passes it to other teammates (usually running guards). This player runs forward with the ball, which is called rushing (or running array).

The quarterback throws the ball to any legal receiver in his team within a certain distance, which is called passing. Passing the ball forward is the characteristic of American football. The attacker can only pass the ball forward once per attack, and can only throw the ball forward behind the offensive and defensive line. Long-distance prequel is usually called "Hail Mary Biography" because it is too difficult, easy to be intercepted and the success rate is too low. Most passers-by are secretly praying for the help of the gods.

There is no limit to the number and position of cross and back pass, but there is a great chance of being intercepted by the opponent when attacking, so American football rarely crosses or back passes, which is a very difficult technique.

Several situations in which the attack opportunity is lost:

1, the player with the ball is tackled to the ground by the defender, resulting in touching the ball (touching the ball to the ground), or the referee thinks that his attack has been tackled by the opposing player.

2. The ball thrown forward by the quarterback is out of bounds or touches the ground before anyone receives it, which is called "unsuccessful passing". After failing to pass the ball forward, put the ball back to the original offensive and defensive line position and start again after using up the first attack.

The player with the ball is out of bounds.

In addition, if one team scores, or a player's helmet falls off, the attack opportunity is over. This is called a dead ball. The referee will whistle.

Players and spectators usually need to know how many attacks they have and how many yards they have left before they can get four chances. For example, before the first attack, TV or scoreboard will write: "1ST&; 10 "(1attack 10 code), which means" this is the first attack, and the target is 10 code (only in this way can we successfully accumulate the distance of10 code) ". If an attack moves forward 3 yards, it will become: "2nd &；; 7 "(7 yards for 2 attacks), that is," the second attack, the goal is to move forward 7 yards "... and so on. However, if the attacker has scored within 10 yards from the score line, he will not report the required number of yards, but the number of times he tried to score "1st&; Target "(1 attack score) and so on. The attacker can keep the ball until:

1, the attacker failed to achieve a new first achievement-in other words, he failed to advance ten yards in four attacks. The defender can start to fight back at the end of the last attack. This exchange of offense and defense is called a mistake.

2. Offensive touchdown score or score. Then the team that scored the original attack will send a special team to kick off for the other team.

3. The attacker gives up kicking. Usually, if the attacker fails to advance ten yards in the first three gears and the position is beyond the shooting distance, in order to avoid giving the opponent a chance to start attacking there after the exchange of offense and defense, he will kick the kick to clear the way in the fourth gear.

The defender intercepts the ball of the attacker, which is called interception. Defender, steals the ball can immediately move to the opponent's end zone until he is intercepted, out of bounds or scores. If he is not touched by any of the original offensive players, causing his body parts other than his hands and feet to land, he will not fall to the ground in contact at this time, and he can continue running until he is tackled by the opposing team or hit the ground. The same rule applies to the catcher on the offensive side.

5. The attacking player drops the ball to the ground, that is, loses the ball, and the defending player gets it first. Like interception, defenders can counterattack in real time when they get the ball dropped by the other side until it is tacked, out of bounds or scored.

* The balls dropped and intercepted by the attacker are collectively referred to as mistakes.

6. The attacker failed in his attempt to shoot. Defenders can start attacking from the last tee (in the NFL, where they shoot). If the shooting place is within 20 yards before the baseline, the original defender will attack at the 20-yard line.

7. Attackers are rarely caught, out of bounds or fouled in their own end zone, which is called safety.

If this happens, attack and defense are equal-the attacker loses possession of the ball and becomes the defender, and the defender becomes the attacker. The scoring methods of both sides are as follows:

1, touchdown score (TD), 6 points. Touchdown refers to the player running into the opponent's end zone with the ball, or receiving a pass in the opponent's end zone (provided that the foot must land when catching the ball, and the ball is not dropped or pushed out of the end zone before landing). The English word "touchdown" means "touching the ground", which comes from football (the ball must touch the ground to be effective when holding the ball in the division), but there is no rule of "touching the ground" in American football, as long as the ball passes above the end line area when holding the ball. In NFL rules, as long as any part of the sphere, no matter how much, enters the end zone, a touchdown score can be formed. In addition, any post on the four corners of the contact end area of the ball can also be regarded as a touchdown score, provided that the ball holder is not thrown to the ground before contact.

After the touchdown, the scoring team got a chance to try to add points (or switch). The ball will be placed on the opponent's 3-yard line (NFL is 2-yard line). The scoring team can choose to kick the ball into the goal and add 1 point, which is called the touchdown score (PAT); Abbreviation); Or score another touchdown by running, passing, etc. , and get a 2-point conversion. In college and professional competitions, most of them add 1 point to shooting. The success rate of professional match 1 point is 94%, that of university league match is 93.8%, and the success rate of 2 points is only about 43%. If the defender successfully stops the bonus of 2 points and grabs the ball and successfully counters the touchdown, he can score 2 points (not applicable to NFL).

2, shooting (shooting, abbreviated as FG), scored 3 points. The method is to kick the ball over the goal crossbar and between the two goalposts. If the ball hits the post and bounces back, it is judged as a failure to shoot. When shooting, the ball must land first. Usually, the ball holder is responsible for pressing the ball vertically to the ground, and then the kicker kicks the ball out. This is called positioning ball. Another unusual method is that the kicker throws the ball in a normal straight way, but the kick time is slightly delayed and kicked at the moment when the ball just touches the ground. This method is called drop kick. Usually when the attacker is close to the scoring line, but it is difficult to advance enough yards before the end of the fourth attack, or the time is too tight to score in other ways, he will choose to shoot. If you miss the shot in high school, you will give the ball control to the defender, but you can still keep the ball control without attacking in the fourth gear of college.

3. Safety (safety, commonly known as "suicide ball"), 2 points. When the attacker is forced to retreat to his own end line area and is caught or dropped, the defender scores 2 points. Some attacks by the attacker in his own end zone will also be rewarded with safety points by the defender. When there is a violation of the rules or disturbing the fair order of the game, the referee will throw a small yellow flag near the foul place. Most penalties are to move the ball to the foul side's end zone for a certain distance. If the number of yards punished by the defender is enough for the attacker, the attacker will automatically get a new first attack. After the game is stopped, the party without foul has the right to choose to accept the penalty or the result of the game at that time. For example, if the defender is offside or moves ahead of time, but the attacker successfully advances 8 yards in this attack, then the attacker can choose to accept the penalty, that is, get 5 yards and launch the first attack again (it takes 5 yards); Or choose to accept the result of the game and give up the penalty for the next attack (advance 2 yards).

Common fouls are:

1. Snatch: The attacker moves before serving, except that one player moves in parallel behind the line. Penalty: Stand back 5 yards.

2. Offside: Before serving, the player crosses the position of the ball. If he touches the opposing player, he crosses into the neutral zone. Penalty: Stand back 5 yards.

3. Holding the ball: improper use of the jersey, hook or shovel hinders the normal movements of the opposing players. If the attacker fouls or just switches between attack and defense, he will be fined 10 yards; If the defender fouls, the penalty will be 5 yards, and the opponent will automatically get a new first attack.

4. Passing interference: When passing the ball, the defender pushes, hooks, pulls or knocks down the catcher of the attacker; Or the receiver of the attacking side will deal with the defending side in the same way to prevent the other side from getting the ball. If the defender fouls, the attacker can choose to accept the foul or refuse it. If the attacker chooses to accept, he will advance 15 yards from the service line and automatically regain 4 attacks. If the attacker refuses (usually, the attacker successfully pushes more than 15 yards in the last confrontation, which exceeds the number of yards fined), he can serve again from the foul place and gain four new offensive rights. If the attacker fouls, stand back five yards. If a player commits a similar foul before passing the ball, he will be sentenced to "pulling people" or "illegal contact"

5. Personal foul: There are six reasons: roughly hitting the passer, roughly hitting the kicker, roughly hitting the player, pulling the opponent's mask, bending down to hit the opponent with his helmet, and jumping at the opponent after blocking the opponent's shot (but if the defender is already in his yard, it is not a foul). The punished party retreated 15 yards. If the defender fouls, the opponent pushes 15 yards and automatically gets the first attack.

6. Game delay: After the 40-second confrontation timer returns to zero, the attacker still fails to serve. Punish the quarterback and step back five yards.

7. Illegal forward pass: the attacker passes the ball forward in front of the offensive and defensive line. Step back five yards and consume one gear.

8. Illegal formation: The offensive line of the attacker is less than seven people.

9. There are too many people on the court: when serving, any party who exceeds 1 1 will be fined and will retreat 5 yards. (Note: It is legal that the number of any party in the confrontation is less than 10. For example, in the 2007 season, in order to commemorate the defender Shane Taylor who was robbed and killed at home, the Washington Redskins specially lined up a ten-man lineup in the away game against the Buffalo Bills one week after his death. )

10, illegal shift: the attacking player can change positions before serving, but only the player behind the offensive and defensive line, and only one player at a time. The attacker can make a translocation after the teammate stops, and other players or illegal players will be fined 5 yards. Defenders are not subject to this restriction.

1 1. Illegal receiver: The legal receiver of the attacking side refers to the two players standing on the outermost front line and all defenders (players behind the service line); It will be considered a foul for the attacker to cross the service line when passing the ball, and he will step back 5 yards.

12. Unsportsmanship: There are many reasons for punishment, which will be decided by the referee. Common ones are: deliberately hitting the referee, verbally abusing the referee, deliberately extending the celebration time after the goal, and continuously using the suspension to freeze the opponent's kicker (the defender called the suspension to freeze the opponent twice before the kicker kicked off, which increased psychological pressure). Penalty: return 15 yards.

If the number of yards fined for a foul exceeds the target line of the first attack, the attacker will also get a new first attack on his own (for example, when the defender has a player offside in "2 attacks and 3 yards", the attacker can get a new first attack). If the back code line of attack and defense is located in the end zone, the ball is placed at the starting point of the 2-code line; If the offensive and defensive sides foul within their own 2-yard line, no matter how many yards they are fined, the number of yards they are fined will become half of the distance from the end zone, and the other side will not get a safety point until part of the ball enters the end zone (in the 2009 Super Cup, Pittsburgh pittsburgh steelers was fined a safety point in the same situation). The line of scrimmage (also known as the line of scrimmage) is the characteristic of American football, and it is also the key feature of its independence from rugby style. Rugby is a long snake advancing side by side. The word "scrummage" comes from scrum (or scrummage) in rugby, that is, the strikers on both sides of the game form a group to push each other back for the ball. In American football, the offensive and defensive lines are actually two imaginary straight lines parallel to the scoring line, one is flush with the front end of the ball (scribbled defensive line) and the other is flush with the back end of the ball (scribbled offensive line), which is used to distinguish the two players. Both sides are fighting for the ball on both sides of the offensive and defensive line.

The distance between the two offensive and defensive lines is also the length of the sphere itself, and the long and narrow virtual zone formed across the stadium is called neutral zone. Before the attack, players from both sides are not allowed to enter or cross the neutral zone, otherwise they will be punished for moving ahead of time or offside-except the attacking center, of course, because he must reach into the neutral zone to touch the ball before serving.

The "offensive and defensive line" usually refers to the defensive line, because the cumulative propulsion distance required by the attacker is based on the position of the front end of the ball. According to NFL rules, there must be at least 7 players on the offensive line in each game. That is to say, in addition to five lineguards, there must be at least two offensive ends arranged on the offensive and defensive line (all "online" behind the line 1 yard). These two ends are usually taut, left/right receiver. Among the players on the offensive and defensive line, only the two outermost players are legal receivers, and the rest are illegal receivers. It is not allowed to pass directly to the quarterback (unless the ball has been touched by other legal receivers), nor is it allowed for the quarterback to initiate a forward pass before the offensive and defensive line. But everyone on the defensive end and any player outside the offensive line 1 yard can catch the ball at will.

Modern video broadcasting technology can use computers to virtually draw offensive and defensive lines (usually blue lines) on the screen, and the effect can be realistic enough to make people feel that they are really drawn on the field. The scale ("X attack X code") and the virtual target line (usually yellow line) that accumulate the advancing distance required by the attacker can also be drawn in real time, which is convenient for TV viewers to know the progress of the game.