In American and Canadian football, a line of scrimmage is an imaginary transverse line (across the width of the football field) beyond which a team cannot cross until the next play has begun. Its location is based on the spot where the ball is placed after the end of the most recent play and following the assessment of any penalty yards.
A line of scrimmage is parallel to the goal lines and touches one edge of the ball where it sits on the ground prior to the snap. Under NCAA, and NFHS rules, there are two lines of scrimmage at the outset of each play: one that restricts the offense and one that restricts the defense. The area between the two lines (representing the length of the ball as extended to both sidelines) is called the neutral zone. Only the offensive player who snaps the ball (usually the center or long snapper) is allowed to have any part of his body in the neutral zone. In order for there to be a legal beginning of a play, at least seven players on the offensive team, including two eligible receivers, must be at, on or within a few inches of their line of scrimmage.
In American football, the set distance of the line of scrimmage between the offense and defense is 11 inches (28 cm), the length of the ball. In Canadian football, the set distance of the line of scrimmage is 1 yard (91 cm), almost three times as long as the American line.
Many fans and commentators refer colloquially to the entire neutral zone as the "line of scrimmage," although this is technically not correct. In the NFL rulebook, only the defensive-side restraining line is officially considered a line of scrimmage. Referees, when explaining a penalty, will refer to "the previous spot" instead of the "line of scrimmage" in order to avoid confusion.
Modern video techniques enable broadcasts of American football to display a visible line on the screen representing the line of scrimmage. The line is tapered according to camera angle and gets occluded by players and other objects as if the line were painted on the field. The line may represent the line of scrimmage or the minimum distance that the ball must be moved for the offensive team to achieve a first down.
The line of scrimmage first came into use in 1880. Developed by Walter Camp (who introduced many innovations that are part of the modern game of American football), it replaced a contested scrimmage that had descended from the game's rugby roots. This uncontested line of scrimmage would set into motion many more rules that led to the formation of the modern form of American football.
The 40-yard dash is a sprint covering 40 yards (36.58 m). It is primarily run to evaluate the speed and acceleration of American football players by scouts, particularly for the NFL Draft but also for collegiate recruiting. A player's recorded time can have a heavy impact on his prospects in college or professional football. This was traditionally only true for the "skill" positions such as running back, wide receiver, and defensive back, although now a fast 40-yard dash time is considered important for almost every position. The 40-yard dash is not an official race in track and field athletics and is not an IAAF-recognized race.
The origin of timing football players for 40 yards comes from the average distance of a punt and the time it takes to reach that distance. Punts average around 40 yards in distance from the line of scrimmage, and the hangtime (time of flight) averages approximately 4.5 seconds. Therefore, if a coach knows that a player runs 40 yards in 4.5 seconds, he will be able to leave the line of scrimmage when a punt is kicked, and reach the point where the ball comes down just as it arrives.46 defense
The 46 defense is an American football defensive formation, an eight men in the box defense, with six players along the line of scrimmage (4 playing line technique, 2 in a linebacker technique). There are two players at linebacker depth playing linebacker technique, and then three defensive backs. The 46 defense was originally developed and popularized with the Chicago Bears by their defensive coordinator Buddy Ryan, who later became head coach of the Philadelphia Eagles and Arizona Cardinals.
Unlike most defensive formations that take their names from the number of defensive linemen and linebackers on the field (i.e. the 4–3 defense has 4 linemen and 3 linebackers), the name "46" originally came from the jersey number of Doug Plank, who was a starting strong safety for the Bears when Ryan developed the defense, a role typically played in the formation as a surrogate linebacker.American football field
The rectangular field of play of American football games measures 100 yards (91.44 m) long between the goal lines, and 160 feet (48.8 m) (53 1⁄3 yards) wide. In addition, there are end zones extending another 10 yards (9.144 m) past the goal lines to the "end lines", for a total length of 120 yards (109.7 m). When the "football field" is used as unit of measurement, it is usually understood to mean 100 yards (91.44 m), although technically the full length of the official field, including the end zones, is 120 yards (109.7 m).
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. In most forms of professional football in the U.S., including the National Football League and most forms of indoor football, the hash marks are in line with the goal posts, both being 18 feet 6 inches apart in the NFL and between 9 and 10 feet in indoor football. High school football and college football fields have hash marks significantly wider than the goal posts. The college football standard, which was the previous standard in the NFL from (1945 to 1971), is 40 feet apart, (20 yards from the sidelines) introduced in 1993. Previously, the college width was the same as the high school standard, at one-third of the width of the field (531⁄3 feet). Yard lines, which can run the width of the field, are marked every 5 yards (4.6 m). A one yard long line is placed near 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; this is to denote the line of scrimmage for a point after touchdown kick (the NFL moved up the line of scrimmage for such kicks to the 15-yard line in 2015, but the dash is still there to denote the line of scrimmage for a two-point conversion). Numerals that display the distance from the closest goal line in multiples of ten (up to the 50 yard line) are placed on both sides of the field every ten yards, with arrows right by the numerals to indicate the closer goal line; some fields may denote the goal line with a "G". Weighted pylons are placed on the inside corner of the intersections of the sidelines, goal lines, and end lines. Including the end zones, the total area of an American football field is 57,600 square feet (5,350 m2).
The goalposts are located at the center of the plane of each of the two end lines. The crossbar of these posts is 10 feet (3.048 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. The uprights extend vertically 35 feet on professional fields, a minimum of 10 yards on college fields, and a minimum of ten feet on high school fields. Goal posts are padded at the base, and orange ribbons are normally placed at the tip of each upright.According to the high school rulebook recommendations, the field should be angled at approximately 1.2° (rising 1⁄4 inch per foot, or 1 in 48) upward from each sideline to the center of the field so that the center is 20 inches (51 cm) higher than the sidelines.American football positions
In American football each team has 11 players on the field at one time. The specific role that a player takes on the field is called their position. Under the modern rules of American football, teams are allowed unlimited substitutions; that is, teams may change any number of players after any play. This has resulted in the development of three "platoons" of players: the offense (the team with the ball, which is trying to score), the defense (the team trying to prevent the other team from scoring, and to take the ball from them), and the special teams (who play in kicking situations). Within those platoons, various specific positions exist depending on what each player's main job is.Burnside rules
The Burnside rules were a set of rules that transformed Canadian football from a rugby-style game to the gridiron-style game it has remained ever since. Named after John Thrift Meldrum Burnside, captain of the University of Toronto football team (although he did not originate them), and first adopted by the Ontario Rugby Football Union in 1903, the rules introduced sweeping changes to the way football was played. The rules included:
a reduction from 15 to 12 players per side
a reduction from 8 to 6 men allowed on the line of scrimmage when the ball was put into play
the "snap-back" system in which the ball was passed backward from the line of scrimmage by the centre
a requirement for a team to make ten yards in three successive downs or lose possession of the ballAlthough similar to American football rules already in place at the time, which had been developed by Walter Camp in the 1880s, Burnside rules had many differences and evolved separately. Although these rules are standard today, at the time they were considered radical. Other teams outside the Ontario Rugby Football Union refused to adopt them until 1905.Defensive back
In American football and Canadian football, defensive backs (DBs) are the players on the defensive team who take positions somewhat back from the line of scrimmage; they are distinguished from the defensive line players and linebackers, who take positions directly behind or close to the line of scrimmage.The defensive backs, in turn, generally are classified into several different specialized positions:
Free safety – most often the deepest safety
Strong safety – the bigger more physical safety, much like a small, quicker linebacker
Defensive halfback (Canadian football only)
Cornerback – which include:
Nickelback – the fifth defensive back in some sets, such as the nickel formation
Dimeback – the sixth defensive back in some sets, such as the dime formation
The seventh defensive back, in the exceedingly rare "quarter" set, but often strong
known as a dollar back or a quarter back (not to be confused with the offensive player who throws the ball)The group of defensive backs is known collectively as the secondary; being the second line of defense after the lineman and guards. They most often defend the wide receiver corps; however, at times they may also line up against a tight end or a split out running back.End (gridiron football)
An end in American and Canadian football is a player who lines up at either end of the line of scrimmage, usually beside the tackles. Rules state that a legal offensive formation must always consist of seven players on the line of scrimmage and that the player on the end of the line constitutes an eligible receiver.
Before the advent of two platoons, in which teams fielded distinct defensive and offensive units, players that lined up on the ends of the line on both offense and defense were referred to simply as "ends". The position was used in this sense until roughly the 1960s.On offense, an end who lines up close to the other linemen is known as a tight end and is the only lineman who aside from blocking can run or catch passes. One who lines up some distance from the offensive line is known as a split end. In recent years and the proliferation of the forward pass, the term wide receiver covers both split ends and flankers (wide receivers who line up in split positions but behind the line of scrimmage). The terms “split end” and “flanker” are often replaced today with terms like "X" and "Z" receivers. Bill Carpenter was the first "Lonesome end."
On defense, there is a commonly used position called the defensive end. Its primary role is to rush the passer, as well as to stop offensive runs to the outer edges of the line of scrimmage (most often referred to as "containment"). However, as there are no rules regulating the formation of the defense, players at this position commonly take on and share multiple roles with other positions in different defensive schemes.Flat route
A flat route is an American football route, used in passing plays. A flat route is usually run by a running back or a fullback. When run by a receiver it can be known as a speed out or arrow route. The eligible receiver runs parallel to the line of scrimmage till near the sidelines (in the flat) and turns toward the quarterback to wait for the pass. The QB's pass should arrive when he has not yet past the line of scrimmage. The receiver will then turn upfield at the sideline and run straight down the field.
The route is used, sometimes as a safety relief if post are covered, with long post, long corner or fly routes, so the safeties and the cornerbacks should be upfield when the pass is caught by the RB or FB. There should be a linebacker covering the RB/FB on these kinds of plays, which is likely to be an easy match for an elusive runner like the running back.Formation (American football)
A formation in football refers to the position players line up in before the start of a down. There are both offensive and defensive formations and there are many formations in both categories. Sometimes, formations are referred to as packages.Glossary of American football
The following terms are used in American football, both conventional and indoor. Some of these terms are also in use in Canadian football; for a list of terms unique to that code, see Glossary of Canadian football.Jump shift
The jump shift or Heisman shift, was an American football shift maneuver utilized by John Heisman. In this system, only the center was on the line of scrimmage, and the backfield would be in a line, as one would in an I-formation with an extra halfback at the hind end, or a giant T. The players could shift into various formations. In one version, the line shifted so that the center was between guard and tackle, and the three back nearest the line of scrimmage would shift all to one side. A split second elapsed, then the ball was snapped and the wall of three blockers charged on. If needed, the center could also snap it to one of the other backs. The phalanx of blockers resembled the yet-to-be developed single wing. The Heisman shift was considered more complicated than its predecessors (say the Minnesota shift).Lineman (gridiron football)
In gridiron football, a lineman is a player who specializes in play at the line of scrimmage. The linemen of the team currently in possession of the ball are the offensive line, while linemen on the opposing team are the defensive line. A number of NFL rules specifically address restrictions and requirements for the offensive line, whose job is to help protect the quarterback from getting sacked for a loss, or worse, fumbling. The defensive line is covered by the same rules that apply to all defensive players. Linemen are usually the largest players on the field in both height and weight, since their positions usually require less running and more strength than skill positions.Miami 4–3 defense
I believed, and still do, in creating upfield pressure from a 4–3 stack formation
The Miami 4–3, also called the 4–3 slide, is a scheme closely associated with the Jimmy Johnson-led Miami Hurricanes, and taken by Johnson to the Dallas Cowboys. Built around Jimmy Johnson's notion of "upfield pressure", it is a penetrating, swarming defense, with a "get there firstest with the mostest" mentality. The focus is to cause opponents to make mistakes, even if the defense might give up a big gain or two. Compared to older 4–3 defenses, such as Tom Landry's 4–3 inside, the defensive line assignments are simpler. Linemen don't read then react, they act then read. Linebackers fill the gaps the linemen leave behind, ignoring gaps away from the play. Coverages are simple, and the playbook small and easy to learn.
The base Miami front is an "over" front, with a nose tackle shaded weak side to the center, a defensive tackle shaded outside the strong side guard, a defensive end shaded outside the tight end, and the weakside end outside the offensive tackle. Each lineman is assigned one gap. Linebackers are stationed about 4 to 4.5 yards behind the line of scrimmage. This differs from the old Landry 4–3 defenses, in which linebackers are within 1.5 yards of the line of scrimmage.The Miami 4–3 uses smaller, faster players than other standard defenses. Defensive ends for the Miami 4–3 are often former linebackers. Outside linebackers are often converted safeties. Players are chosen for speed and aggression more than size and power. The middle linebacker is the one true linebacker, the tackles the two true linemen in this defense.Offensive backfield
The offensive backfield is the area of an American football field behind the line of scrimmage. The offensive backfield can also refer to members of offense who begin plays behind the line, typically including any backs on the field, such as the quarterback, halfbacks and fullback.Punt (gridiron football)
In American and Canadian football, a punt is a kick performed by dropping the ball from the hands and then kicking the ball before it hits the ground. The most common use of this tactic is to punt the ball downfield to the opposing team, usually on the final down, with the hope of giving the receiving team a field position that is more advantageous to the kicking team when possession changes. The result of a typical punt, barring any penalties or extraordinary circumstances, is a first down for the receiving team. A punt is not to be confused with a drop kick, a kick after the ball hits the ground, now rare in both American and Canadian football.
The type of punt leads to different motion of the football. Alex Moffat invented the now-common spiral punt, as opposed to end-over-end.Quarterback sack
In American football and Canadian football, a sack occurs when the quarterback (or another offensive player acting as a passer) is tackled behind the line of scrimmage before he can throw a forward pass, when the quarterback is tackled behind the line of scrimmage in the "pocket" and his intent is unclear, or when a passer runs out of bounds behind the line of scrimmage due to defensive pressure. This often occurs if the opposing team's defensive line, linebackers or defensive backs are able to apply pass pressure (also called a pass rush) to quickly get past blocking players of the offensive team (the quarterback's protection), or if the quarterback is unable to find a back to hand the ball off to or an available eligible receiver (including wide receivers, running backs and tight ends) to catch the ball, allowing the defense a longer opportunity to tackle the quarterback.
Performing a sack is advantageous for the defending team as the offense loses a down, and the line of scrimmage retreats several yards. Even better for the defense is a sack causing the quarterback to fumble the ball at or behind the line of scrimmage; this is also known as a strip sack and can result in a turnover if the defense manages to obtain the ball. A quarterback that is pressured but avoids a sack can still be adversely affected by being forced to hurry.
In the National Football League (NFL), it is possible to record a sack for zero yards. The QB must pass the statistical line of scrimmage to avoid the sack. If a passer is sacked in his own end zone, the result is a safety and the defending team is awarded two points, unless the football is fumbled and either recovered in the end zone by the defense for a touchdown or recovered by either team outside the end zone.Reception (gridiron football)
In American football and Canadian football, a reception, also known informally as a catch, is part of a play in which a forward pass from behind the line of scrimmage is received (caught) by a player in bounds, who, after the catch, proceeds to either score a touchdown or be downed. Yards gained from the receiving play are credited to the receiver as receiving yards. If such a pass is not caught by the receiver, it is called an incomplete pass or simply an incompletion.
A reception should not be confused with a lateral, also known as a lateral pass or backward pass, which occurs when the ball is thrown backwards or sideways to a teammate (that is, no part of the pass trajectory is toward the opponent's goal line).Slotback
Slotback, sometimes referred to as an A-back or, especially in the United States, slot receiver, is a position in gridiron football. The "slot" is the area between the last offensive lineman on either side of the center and the wide receiver on that side. A player who lines up between those two players and behind the line of scrimmage is a slotback. The position is a fixture of Canadian football and indoor football, but is also used in American football. The slotback is similar to the wide receiver but also has many of the same traits as a running back or tight end; a slotback lines up closer to the offensive line and often farther back than a wide receiver.
Slotbacks are often as many as five yards behind the line of scrimmage when the ball is snapped and, in the Canadian and indoor game, may also make a running start toward the line of scrimmage prior to the snap. In most forms of American football, this would be an illegal motion, although a few professional leagues such as the World Football League and XFL allowed forward motion.Wide receiver
A wide receiver, also referred to as wideouts or simply receivers, is an offensive position in American and Canadian football, and is a key player. They get their name because they are split out "wide" (near the sidelines), farthest away from the rest of the team. Wide receivers are among the fastest players on the field. The wide receiver functions as the pass-catching specialist.
Gridiron football concepts
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