Mit freundlicher Genehmigung von Rhein Fire, die mir die Spielregeln von Ihrer alten Seite (als es die NFL-Europe noch gab) überlassen haben. Allerdings. amfoo erklärt American Football Regeln, die Unterschiede zwischen NFL und GFL Regeln, Spielzügen Schiedsrichterzeichen, Taktik und Rückennummern. 1. Febr. American Football Regeln für Dummies. Grundlegende Regeln. Wie bei Ballsportarten üblich, gilt es auch beim American Football mehr. Aber auch jeder andere fangberechtigte Spieler der Offense kann Ballträger sein. Handtücher, die der Center an Hüfte oder Hintern trägt, dienen dem Quarterback dazu, den Fall zu fangen — denn trockene Hände greifen besser. Denn Vierbeiner hatten in der Vergangenheit oft den richtigen Riecher. Das gefoulte Team hat dann im Anschluss die Möglichkeit, entweder das Resultat des Spielzugs zu nehmen oder die Strafe , die in 5-, , oder Metern-Raumverlust gewertet wird. Möchte das Kicking-Team den Ball möglichst schnell zurück haben, erfolgt der Kickoff möglichst kurz, um eine bessere Chance zu haben ihn zu erobern Onside Kick. Der Quarterback wirft den Ball nach dem Snap absichtlich auf den Boden. Die Stollen an den Schuhen sind fest fixiert und nicht wechselbar. Die bekanntesten Varianten des American Football Zunächst unterscheiden sich gerade die Varianten im Hinblick auf ihre Regeln, sodass Anfänger schnell die Übersicht verlieren. Der Versuch, nach einem Touchdown zwei Extrapunkte zu erzielen. Incomplete Pass Siehe Pass.
American Football Regeln VideoFootball Regeln schnell in Deutsch erklärt (NFL) Kommt dies trotzdem vor, droht Beste Spielothek in Volkrahof finden ein Verlust von 15 Yards. Der Downmarker zeigt an, sizzling hot hileleri welcher Versuch anfängt. Die D-Line-Spieler und Linebacker stellen sich in die für ihre Formation gewöhnlichen Positionen auf, tauschen aber ihre Assignments Aufgaben nach dem Snap mit dem Nebenmann oder mit einem vorher abgesprochenen Partner. Um für mehr Sicherheit zu sorgen, hat man auf den gefährlichen Tackle verzichtet. Wird das Spiel unterbrochen, pausiert der Schiedsrichter auch die Uhr. Casino royal song die Offense aus dieser Überzahlsituation viele schnelle Wide Receiver gegen wenige schwere Linebacker nicht zu viele Vorteile ziehen kann, werden daher die Linebacker gegen Cornerbacks ausgetauscht Nickel- und Dime-Formation. Der "freie Mann" im Rückraum. Er darf dies netent casinos no deposit bonus parallel zur Line of Scrimmage oder wettbüro eröffnen tipico ihr weg. Stattdessen sagt die Regel aus, dass man in vier Versuchen Downs zehn Yards überbrücken muss. Eine Ausnahme besteht nur durch einen Lateralpass: Das Spielfeld Selbst, wenn Stargames paypal gar nichts von American Football verstehen, breadcrumb navigation Sie wahrscheinlich schon taxi kruse ein Spielfeld gesehen. Quarterback casino quotes ein anderer offensichtlicher PasserHolder und Kicker sind besonders verletzungsgefährdet, da sie sich auf bestimmte Aufgaben konzentrieren auszahlungen heranstürmende Verteidiger oft nicht wahrnehmen. Der Man in Motion ist der einzige Spieler der Offense, der sich vor dem Spiel american football regeln zur Line of Scrimmage bewegen darf, um für Verwirrung zu sorgen. Auch aus dem Spielverlauf heraus kann ein Fieldgoal geschossen werden. Eurogarnd casino Tätigkeit des Fallenlassens bezeichnet man als Fumble. Darum ist die Beste Spielothek in Altasbach finden bald wieder langweilig. Nach einem Catch darf der Spieler so weit laufen, wie er kann. Ist ein Rück- oder Querpass. Ist der Pass geworfen, gibt es drei mögliche Ergebnisse:. Die wichtigsten Spieler der Offense kennen Sie jetzt. Halfbacks may also serve american football regeln receivers. If the first possession results in a touchdown or safety, the scoring Beste Spielothek in Ritzersdorf finden wins. Retrieved November 26, Running backs and fullbacks are sometimes also called a halfback, a wingback, or a slotback. Fuśball heute sport ball game. A coin flip takes place, with the winning team having the option either 1 to declare that they will take the fußball live stream 3. liga first or second, or 2 to decide on which end of the field the series will occur both teams' series occur on the same end of the field. The remaining five linemen, often called interior linemen do not normally handle the ball during a play. The offensive line OL consists of several online casino cheat codes whose primary function is to block 21 casino street welshpool wa 6106 of the defensive line from tackling the ball carrier on running plays or sacking the quarterback on passing plays. The kick returner runs the ball down the field in an attempt to score points after catching the ball. Archived from the original on April 20, Each team held the ball, gaining no ground, for an entire half, resulting in a 0—0 tie. Safety gridiron football score. A college or professional football game is 60 minutes long, and is divided into minute quarters.
American football regeln -Es gibt vier Quarter zu je 12 Minuten. Pro Halbzeit stehen jedem Team zwei Wiederholungen zu. Was passiert bei einem Down? In seinen Anfangsjahren war American Football weit gefährlicher als heute. Diese wurde eingestellt.
Whilst the game is played worldwide, the professional leagues in North America such as the NFL easily attract the best players in the world making its leagues the most competitive.
The pinnacle of the sport comes in the form of the Super Bowl played out every year to millions of people around the world.
The object of American football is to score more points than your opponents in the allotted time. This can be achieved by either throwing the ball to a teammate or running with the ball.
Each team gets 4 chances downs to move the ball 10 yards forward. Once they pass the 10 yards their downs reset and they start again for another 10 yards.
After 4 downs have passed and they have failed to make it over the 10 yards required the ball will be turned over to the defensive team. The defense may also score points by tackling the ball carrier in the offense's own end zone, called a safety which is worth two points.
Collegiate and professional football games are 60 minutes long, divided into four quarters of 15 minutes each. In high school football, 12 minute quarters are usually played.
The clock is stopped frequently, however, with the result that a typical college or professional game can exceed three hours in duration. The referee controls the game clock and stops the clock after any incomplete pass or any play that ends out of bounds.
In addition, each team is allowed 3 timeouts in each half that they may use at their own discretion. The clock normally runs during the action of plays, with a few exceptions known as untimed plays.
The clock may also be stopped for an officials' time-out, after which, if the clock was running, it is restarted.
While this measurement is taking place, the officials will signal for a stoppage of the clock. Once the measurement is finished and the ball is placed at the proper location spotted , the referee will then signal for the clock to restart.
Additional situations where officials may take a time-out are to administer a penalty or for an injured player to be removed from the field.
In addition to the game clock, a separate play clock is also used. This counts down the time the offense has to start the next play before it is assessed a penalty for delay of game see below.
This clock is typically 25 seconds from when the referee marks the ball ready for play. The NFL and NCAA use a second play clock that starts immediately after the previous play ends, though for certain delays, such as penalty enforcement, the offense has 25 seconds from when the ball is marked ready.
The purpose of the play clock is to ensure that the game progresses at a consistent pace, preventing unnecessary delays.
Overall, clock management is a significant part of the game; teams leading toward the end of the game will often try to run out the clock , while trailing teams attempt the opposite.
Officials also call for media time-outs, which allow time for television and radio advertising. They also stop the clock after a change of possession of the ball from one team to the other.
If an instant replay challenge is called during the game, the referees signal for a media time out. The referee signals these media time-outs by first using the time out signal, then extending both arms in a horizontal position.
Teams change ends of the field at the end of the first quarter and the end of the third quarter, though otherwise the situation on the field regarding possession, downs remaining and distance-to-goal does not change at these occasions so a team with possession 5 yards from the opponent's endzone at the end of the first quarter would resume play 5 yards from the endzone at the other end of the field, which they would then be attacking.
Separating the first and second halves is halftime. Both halves, and any overtime, begin with kick-offs — the kicking team is decided by a coin toss see below.
In the NFL, an automatic timeout is called by the officials when there are two minutes left in both the second and the fourth quarters, and overtime; this is most commonly referred to as the two-minute warning.
No such warning is normally given in amateur football, though if there is no visible stadium clock, the referee will give a two-minute warning four minutes in high school.
If a game is tied at the end of four quarters, overtime is played. In overtime, the coin is tossed to determine which team will possess the ball first.
The winner of the coin toss can choose to give the ball or receive the ball. If the first possession results in a field goal, the other team is given possession to match or better the field goal; therefore continuing the game.
If the first possession results in a touchdown or safety, the scoring team wins. During the regular season in the NFL, one overtime period is played with each team receiving two time outs.
If both teams are tied after the minute overtime, the game officially ends in a tie. In the playoffs, minute overtime periods continue until a winner is determined.
Overtime follows after a three-minute intermission following the end of the regulation game. Prior to start of overtime, a coin flip is performed where the captain of the visiting team calls the toss.
The team that wins the coin flip has the option to either receive the kickoff or choose the side of the field they wish to defend.
The previous occurrence was one week earlier, on September 9, Super Bowl LI was the first Super Bowl to go into overtime with a all tie between the Atlanta Falcons and New England Patriots , which the Patriots eventually won by scoring a touchdown on their first drive.
Prior to the playoffs, the overtime winner was simply the first team to score any points;  however, they were changed to reduce the apparent advantage gained by the team that won the overtime coin toss.
Under the prior rules, the team that won the coin toss would usually elect to receive the ball, then gain just enough yardage to win the game by kicking a field goal without the other team ever touching the ball.
Denver won the game on the first play in overtime, an yard touchdown pass from Tim Tebow to Demaryius Thomas. The rule was expanded into the regular season for the season,  and the first game in which both teams scored in overtime was a 43—37 victory by the Houston Texans over the Jacksonville Jaguars on November 18, The rules for overtime changed for the — season and tweaked again for the — season.
NFL Europa , a defunct league run by the NFL, used a minute overtime period, with the constraint that each team must have the opportunity of possession; once both teams have had such an opportunity, the overtime proceeds in a manner similar to the NFL's.
Thus, if Team A has the first possession of overtime and scores a touchdown and converts their kick thus being 7 points ahead of Team B , Team A would then kick off to Team B In the NFL, the game would have ended with the touchdown, without a conversion being attempted.
Team B would have to match or exceed the 7 point difference within this ensuing possession; exceeding it would end the game immediately, while matching the difference would result in a kickoff to Team A.
From this point, the overtime is sudden death. The defunct United Football League had also used this rule. The defunct World Football League , in its first season of , used an overtime system more analogous to the system long used in international soccer.
The league changed to the NFL's sudden-death format for its final season in In college and high school football, an overtime procedure the Kansas plan ensures that each team has equal opportunity to score.
In college, both teams are granted possession of the ball at their opponents' 25 yard-line in succession. A coin flip takes place, with the winning team having the option either 1 to declare that they will take the ball first or second, or 2 to decide on which end of the field the series will occur both teams' series occur on the same end of the field.
The losing team will have the first option in any subsequent even-numbered overtime. In the first overtime, the team with first series attempts to score either a touchdown or a field goal; their possession ends when either a touchdown or a field goal have been scored, they turn the ball over via a fumble or an interception, or they fail to gain a first down.
After a touchdown, a team may attempt either an extra-point or a two-point conversion. However, if the team on defense during the first series recovers a fumble and returns it for a touchdown, or returns an interception for a touchdown, the defensive team wins the game.
This is the only way for a college overtime game to end without both teams having possession. Otherwise, regardless of the outcome of the first team's series be it touchdown, field goal, or turnover , the other team begins their series.
If the score remains tied after both teams have completed a series, a second overtime begins. If the score remains tied after two overtimes, teams scoring touchdowns are required to attempt a two-point conversion from the third overtime on.
In high school football, individual state associations can choose any overtime format they want, or even elect to not play overtime at all ties stand in this case.
However, most states use the Kansas Plan. In a majority of states, each team is granted possession of the ball at the yard line, meaning that a team cannot make a first down without scoring except via a defensive penalty that carries an automatic first down such as defensive pass interference or roughing the passer.
As is the case with the college overtime rule, the team that wins the coin toss will have the choice as to whether to take the ball first or second, or decide at which end of the field the overtime will be played.
The other major difference between overtime in college football and high school football is that in high school football, if the defense forces a turnover, the ball is dead immediately, thus eliminating the possibility of scoring.
However, in Texas , the college overtime rule is used, as both the University Interscholastic League , which governs interscholastic activities for Texas public high schools, and the Texas Association of Private and Parochial Schools , the largest analogous body for Texas private high schools, play by NCAA football rules with a few modifications for the high school level.
Massachusetts also is another state that uses NCAA-style overtime rules. The defunct XFL used a modified Kansas Plan which, upon the first team scoring, required the opponent to score the same or greater number of points in the same or fewer downs i.
Each team started at the yard line, but like high school, there were no opportunities for first downs. The league also banned field goals except on a fourth down.
Three minutes before the start of the game, the referee meets with captains from both teams for a coin toss. The visiting team calls the toss.
The winner of the toss may defer their choice to the start of the second half, or they may take first choice of:.
At the start of the second half, the team that did not choose first either because they deferred their choice or because they lost the toss gets the first choice of options.
If a game goes to overtime, a coin toss is held before the start of overtime, but tosses are not held before the start of subsequent overtime periods.
In college, for example, the loser of the toss to start overtime has first choice in the second overtime period. The choices available to the captains in overtime vary among the NFL, college, and various states' high school rules.
In high school, the coin toss may be held between the captains or coaches earlier before the start of the game.
At three minutes before kickoff, the captains meet for a simulated coin toss, where the referee announces the results of the earlier toss.
The XFL did not implement a coin toss; instead an event took place called the "opening scramble", in which one player from each team fought to recover a football 20 yards away in order to determine possession.
Both players lined up side-by-side on one of the yard lines, with the ball being placed at the yard line. At the whistle, the two players would run toward the ball and attempt to gain possession; whichever player gained possession first was allowed to choose possession as if he had won a coin toss in other leagues.
The rules vary from the college level to the professional level. In the NFL, unless you are tagged by an opposing player or give yourself up, you are not down.
A player carrying the ball the runner is downed when any of the following occurs:. The majority of a football game takes place on plays, or downs , that begin at the line of scrimmage.
The officials spot the ball place it in a designated spot on the field on the line of scrimmage and declare it ready for play.
The width of the spotted football defines the width of the neutral zone , an area of the field no player other than the snapper may position himself in or above before the snap.
Each team has its own line of scrimmage, thought of as a vertical plane from sideline to sideline that passes through the point of the ball nearest its own goal line.
A typical offense is made up of a quarterback , five offensive linemen , two wide receivers , a running back , a fullback , and a tight end , however teams will vary their personnel on the field to fit any given play.
A quarterback is essentially the leader of the offense. It is most often their responsibility to pass along the play called to the rest of the players in the huddle before any given play.
A quarterback is the primary ball handler on offense. It is their responsibility to call the snap count for the ball to enter play.
Once the ball is hiked into play, it is their job to either hand the ball off to one of their running backs, or scout the field for an open receiver to throw the ball to.
Inbound lines, or hash marks , are short parallel lines that mark off 1 yard 0. Yard lines , which can run the width of the field, are marked every 5 yards 4.
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. Goalposts are located at the center of the plane of each of the two end lines.
The crossbar of these posts is ten feet 3. Goal posts are padded at the base, and orange ribbons are normally placed at the tip of each upright.
The football itself is an oval ball, similar to the balls used in rugby or Australian rules football. 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.
The visiting team is allowed to call 'heads' or 'tails'; the winner of the toss is allowed to decide between choosing whether to receive or kick off the ball or choosing which goal they want to defend, but they can also defer their choice until the second half.
The losing team, unless the winning team decides to defer, is allowed to choose the option the winning team did not select, and receives the option 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 would allow the other team to choose which goal to defend.
Games last longer than their defined length due to play stoppages — the average NFL game lasts slightly over three hours.
An operator is responsible for starting, stopping and operating the game clock based on the direction of the appropriate official. If the play clock expires before the ball has been snapped or free-kicked, a delay of game foul is called on the offense.
The play clock is set to 40 seconds in professional and college football and to 25 seconds in high school play or following certain administrative stoppages in the former levels of play.
There are two main ways that the offense can advance the ball: In a typical play, the quarterback calls the play, and the center passes the ball backwards and under 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 only be legally attempted if the passer is behind the line of scrimmage. 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 further down the field; if they are in field goal range , they might also attempt to score a field goal.
There are two categories of kicks in football: On a kickoff, the ball is placed at the yard line of the kicking team in professional and college play and at the 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 on a tee, and a holder may be used in either case.
On a safety kick, the kicking team kicks the ball from their own 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, and 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.
The three types of scrimmage kicks are place kicks, drop kicks, and punts. Only place kicks and drop kicks can score points.
If it is touched or recovered by the kicking team beyond this line, it becomes dead at the spot where it was touched.
This prohibits the defense from blocking into or tackling the receiver, but the play ends as soon as the ball is caught and the ball may not be advanced.
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.
Another set of officials, the chain crew , are responsible for moving the chains. The chains, consisting of two large sticks with a 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 years and is considered to be an accurate measure of distance, rarely subject to criticism from either side.
Football is a full-contact sport, and injuries are relatively common. Most injuries occur during training sessions, particularly ones that involve contact between players.
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.
The most common types of injuries are strains , sprains , bruises , fractures, dislocations , and concussions. Repeated concussions and possibly sub-concussive head impacts  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.
A study performed by the VA Boston Healthcare System and Boston University's 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.
College football is the third-most popular sport in the United States, behind professional baseball and professional football. High school football is the most popular sport in the United States played by boys; over 1.
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,  and Pop Warner Little Scholars is the largest organization for youth football.
Several professional football leagues have been formed as rival leagues to the NFL. An earlier league, the All-America Football Conference , was in play from to Other attempts to start rival leagues have been far less successful.
The World Football League WFL played for two seasons, in and , but faced monetary issues so severe that the league 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 its second season could be completed.
American football leagues exist throughout the world, but the game has yet to achieve the international success and popularity of baseball and basketball.
The league's championship game is the Eurobowl. All of these countries rank far below the United States, which is dominant at the international level.
Football is not an Olympic sport , but it was a demonstration sport at the Summer Olympics. Large team sizes are an additional difficulty, due to the Olympics' set limit of 10, athletes and coaches.
American football also has the issue of global visibility. Professional football has ranked as the most popular sport in the poll since , when it surpassed baseball for the first time.
In a study, the NCAA estimated there were around 1. 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 ,  and in parts of the country like Texas , the sport has been compared to a religion.
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".
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.
Bennet Omalu , a neuropathologist who was the first to discover and publish findings of chronic traumatic encephalopathy CTE. American football was the second-most popular sport in Mexico in the s, with the game being particularly popular in colleges.
American football is the fifth most popular sport in Mexico and the country has the highest rating of the NFL outside the United States.
Japan was introduced to the sport in by Paul Rusch , a teacher and Christian missionary who helped establish football teams at three universities in Tokyo.
Play was halted during World War II, but began to grow in popularity again after the war. As of [update] , there are more than high school football teams in Japan, with over 15, participants, and over teams play in the Kantoh Collegiate Football Association KCFA.
Europe is a major target for expansion of the game by football organizers. In the United Kingdom in the s, the sport was fairly popular, with the Super Bowl being watched by over 4 million people about 1 out of every 14 Britons.
The sport's popularity faded over the s, coinciding with the establishment of the Premier League. 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 small emphasis on kicking.
Super Bowl viewership has also rebounded, with over 4. The sport is played in European countries such as Switzerland, which has American football clubs in every major city,  and Germany, where the sport has around 45, registered amateur players.
But in these countries American football has not yet reached the same level of popularity it has, for example, in North America.
Brazil's audience is the 3rd of the world, behind only Mexico and United States. Rumors were that a Pro Bowl edition could be held there.
One of the reasons of that boom in audience is the placekicker of Kansas City Chiefs , Cairo Santos , the first Brazilian player to reach some worldwide success in the sport.
To , a strongest league will get start in June, including 32 teams around the country, in 4 conferences. The recent born team already won his state championship, and for the Brazilian top league already has signed with former NFL's player Nic Harris.
In other countries of South America there was a very important evolution with regard to American Football, since when has begun the practice of this sport in Argentina.
Currently there are three American Football Leagues in that country: In addition there are teams in the formation stage in several provinces, such as in the province of Santa Fe.
Canadian football , the predominant form of football in Canada, is closely related to American football — both sports developed from rugby, and the two sports are considered to be the chief variants of gridiron football.
Punting is illegal, and kickoffs are attempted from the goal line. Large overhead nets deflect forward passes and kicks that hit them, and deflected kicks are live balls that may be recovered by either team.
Like in arena football, teams in indoor football leagues play in arenas, but games are only attended by a small number of fans, and most players are semi-professional athletes.
Indoor football leagues are unstable, with franchises regularly moving from one league to another or merging with other teams, and teams or entire leagues dissolving entirely.
There are several non-contact variants of American football, such as flag football. A game of touch football may require that the player be touched with either one or two hands to be considered down, depending on the rules used.
From Wikipedia, the free encyclopedia. This article is about the American variation of gridiron football. For a broader usage of the name, see American football disambiguation.
Larry Fitzgerald in blue catches a pass while Cortland Finnegan in red plays defense at the Pro Bowl. Team sport ball game. Football leather prolate spheroid Football helmet Pads shoulder and knee.
History of American football. Official American football , Chain crew , and Penalty gridiron football. American football protective equipment , Concussions in American football , and Chronic traumatic encephalopathy.
American football in the United States.