In gridiron football, the chain crew (commonly known as the "chain gang") is a crew that manages signal poles on one of the sidelines. There are three primary signal poles: the "rear rod" that marks the beginning of the current set of downs, the "forward rod" that marks the line to gain, and the "box" that marks the line of scrimmage. The two rods are attached at the bottom by a chain exactly ten yards long, while the "box" displays the current down number.
The chain crew, under the direction of the head linesman/down judge, signals the officials' decisions; it does not make decisions. Players look to the chain crew to see the line of scrimmage, the down number, and the line to gain. Officials may rely on the chain crew after a play (incomplete pass or penalty) whose outcome depends on the original spot of the ball. This also includes bringing the chains onto the field whenever an accurate measurement is needed to determine if a first down has been made.
Three members of the chain crew hold poles upright. The bottom of each pole is placed along a sideline to denote a line across the gridiron to the opposite sideline.
There may be additional chain crew members. A "clip man" is discussed below. In the NFL, additional chain crew members have additional tasks, such as to relieve the line judge of the clerical task of recording all assessed penalties. [1] Despite the use of "man" in the colloquial terms for the chain crew positions, women can perform any of them. [1]
Members of the chain crew are usually picked by the offices of the home team instead of the league or conference. In the NFL, members of the chain crew must have credentials entitling them to access to the field, and must wear white shirts. The home team pays them; some teams pay an hourly wage and others pay a flat rate to work a game. [1]
The chain crew does not wear protective gear as players do. A routine instruction by officials to the chain crew is to withdraw or drop their signals, and move back, if the play comes toward them so as to endanger them. Often, the signals use bright orange color, are padded, and have break-away components for safety.
For games at all levels except the NFL, the chain crew operates on the side of the field opposite the press box (usually the visiting team's sideline).
In the NFL, the chain crew switches sides at halftime; the referee determines their initial placement. [note 1]
In the NCAA, the chains are located opposite the press box for the entire game. In the first half, the line judge is located opposite the press box and supervises the chain crew, with the head linesman on the press box side of the field. In the second half, the head linesman and line judge swap sides of the field like in the NFL, with the linesman supervising the chain crew. This practice started in 2014.
In the NFL and other venues where there is a zone behind the sidelines, all three poles are placed somewhere along the back line of this zone. Otherwise, the poles are placed along the sideline.
For professional and college football games, an auxiliary chain crew operates on the opposite side of the field, supervised by the line judge. Their presence lets players and officials look to either side of the field for information.
The auxiliary chain crew also includes a member holding the drive start indicator, which is placed at the beginning of a team's drive and stays there until the team loses possession. This indicator is only used for statistical purposes to calculate the distance of each drive. It looks similar to a "stick" and has an arrow (or occasionally a large "X") that points in the direction the offensive team is going. The NFL eliminated the drive start indicator in 2018. [1]
At the start of a series of downs, the linesman stands so that the heel of one foot marks the initial line of scrimmage. The box man places his indicator to mark this position and sets the box to display "1". The operator of the rear rod marks the same position, while the other rod man moves ten yards toward the defense's goal line to mark the line to gain.
The linesman, the box man, or a fourth member of the chain crew attaches a "clip" to the chain to line up with the rear edge of the closest five-yard line to the rear rod. [2] A device on the clip indicates which numbered line this is. The clip and the device let the chain crew restore the position of the rods after a mishap. In leagues such as the NFL with Instant Replay, there may be multiple clips to let the rods be repositioned after a play is reviewed and reversed. [2]
After a typical play, the box man increments the displayed number and realigns that pole to the new line of scrimmage, again as directed by the linesman. After a play that results in a first down, all three members move and reset their signals to mark a new series of downs.
The chain crew must not move until the referee or linesman signals whether the play finished without a penalty. On a penalty, the chain crew stays put so that the officials can see the original state. When the referee and linesman walk off the appropriate number of yards, the box man moves as well. The box man does not change the number displayed, except on a penalty that results in a loss of down. On a penalty that results in a first down, the entire chain crew moves and resets.
When possession of the ball switches to the other team, the forward rod becomes the rear rod and vice versa to minimize the distance the rod men have to move. However, at the end of the first and third quarters, when players switch directions on the field, the chain crew also moves (for example, a marker may move from one 32-yard line to the other 32-yard line). The rear rod man moves past the forward rod man and continues to mark the start of the series of downs, in the new orientation. The linesman and other officials supervise this movement, using one or more clips to exactly reposition the chains. [3]
On plays where there is no line to gain (a series of downs that starts within 10 yards of the goal line, a try after touchdown, or a kickoff), the rod men lower or lay down their signals, but the box man continues to mark the line of scrimmage.
The chains are brought onto the field whenever the referee needs an accurate measurement to determine if a first down has been made. A team may also request an accurate measurement to determine how far they have to reach for the first down.
Before the game, many linesmen attach a piece of tape at the midpoint of the chain. [4] The linesman can compare the line of scrimmage to this mark at the start of a play and know whether a 5-yard penalty against the defense will result in a first down. If so, the linesman's typical hand signal to the line judge across the field is to extend the arms with the thumbs pointing toward one another. Such a gesture with thumbs pointing away signals that there are more than 5 yards to gain. [5] : 6.10.1
All levels of organized football have used the chain crew. The "box" (down marker) has evolved over time. In the pre-television era, it was a rod (shorter than the height of the operator) with a triangular pointer that rotated to show the official the down number. It was replaced with a much larger, two-sided flipper system when television became widespread; flipper-style down markers are still in use in scholastic and amateur football. A more modern model is the Dial-a-Down, in which compact levers display a new down number over the entire face of the "box"; this model is used at most college and professional games. [1] Electronic down markers using LEDs are emerging as the next advance. [6]
Early attempts and proposals to use precision automatic chain instruments were hindered both by costs and potential hazards (early proposals required metal rails; a 1990s system used visible lasers). [7]
For the 1974 season, the World Football League used the "Dicker-rod," a proprietary stick approximately 3 yards (9.0 ft; 2.7 m) in length, which allowed measurements to be made with one person instead of three.
Lazser Down, which uses wideband radio waves to precisely spot and measure distances, has been used in college football, the Alliance of American Football and the XFL. [7]
The 2022 revival of the United States Football League abolished the chain crew, instead relying on "Firsty," a proprietary remote-sensing system using lidar and a sensor inside the football. [8] [9] When the USFL and XFL merged to form the United Football League, they continued to use a similar technology, "TrU Line." [10]
In July 2024, the NFL announced a partnership with Sony for technology that would use multiple camera views to obviate the chain crew. [11]
Canadian football, or simply football, is a sport in Canada in which two teams of 12 players each compete on a field 110 yards (101 m) long and 65 yards (59 m) wide, attempting to advance a pointed oval-shaped ball into the opposing team's end zone.
Gridiron football, also known as North American football, or in North America as simply football, is a family of football team sports primarily played in the United States and Canada. American football, which uses 11 players, is the form played in the United States and the best known form of gridiron football worldwide, while Canadian football, which uses 12 players, predominates in Canada. Other derivative varieties include arena football, flag football and amateur games such as touch and street football. Football is played at professional, collegiate, high school, semi-professional, and amateur levels.
A down is a period in which a play transpires in gridiron football. The down is a distinguishing characteristic of the game compared to other codes of football but is synonymous with the 6 "tackle" rule in rugby league. The team in possession of the football has a limited number of downs to advance ten yards or more towards their opponent's goal line. If they fail to advance that far, possession of the ball is turned over to the other team. In most situations if a team reaches their final down, they will punt to their opponent, which forces their opponent to begin their drive from further down the field; if they are in range, they might instead attempt to score a field goal.
This is a glossary of terms used in Canadian football. The Glossary of American football article also covers many terms that are also used in the Canadian version of the game.
American and Canadian football are gridiron codes of football that are very similar; both have their origins partly in rugby football, but some key differences exist between the two codes.
Gameplay in American football consists of a series of downs, individual plays of short duration, outside of which the ball is or is not in play. These can be plays from scrimmage – passes, runs, punts or field goal attempts – or free kicks such as kickoffs and fair catch kicks. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.
In gridiron football, clock management is an aspect of game strategy that focuses on the game clock and/or play clock to achieve a desired result, typically near the end of a match. Depending on the game situation, clock management may entail playing in a manner that either slows or quickens the time elapsed from the game clock, to either extend the match or hasten its end. When the desired outcome is to end the match quicker, it is analogous to "running out the clock" seen in many sports. Clock management strategies are a significant part of American football, where an elaborate set of rules dictates when the game clock stops between downs, and when it continues to run.
In American football, the Fog Bowl was the December 31, 1988 National Football League (NFL) playoff game between the Philadelphia Eagles and Chicago Bears. A dense fog rolled over Chicago's Soldier Field during the 2nd quarter, cutting visibility to about 15–20 yards for the rest of the game. The Eagles moved the ball effectively all game and their quarterback Randall Cunningham recorded 407 passing yards despite the low visibility; but they could not advance the ball into the end zone. Many players complained that they could not see the sidelines or first-down markers. The Bears ended up winning the game by a score of 20–12. The game eventually was named #3 on NFL Top 10's Weather Games.
In gridiron football, an official is a person who has responsibility in enforcing the rules and maintaining the order of the game.
A formation in American 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.
A comparison of American football and rugby union is possible because of the games' shared origins, despite their dissimilarities.
The rectangular field of play used for American football games measures 100 yards (91.44 m) long between the goal lines, and 160 feet (48.8 m) wide. The field may be made of grass or artificial turf. 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). The total area of the field is 57,600 sq ft or 5,350 m2. There is a goal centered on each end line, with a crossbar 10 feet (3.0 m) above the ground and goalposts 18 feet 6 inches (5.64 m) apart extending at least 35 feet (11 m) above the crossbar. Between the goal lines, additional lines span the width of the field at 5-yard intervals. This appearance led to the use of the term gridiron in the 1880s. For a few years in the early 20th century, lines perpendicular to the lines at 5-yard intervals spanned the length of the field, giving it a checkerboard-like appearance.
The dicker-rod is a device intended to replace the first down chains commonly used to measure 10-yard distances during games of gridiron football. The device was named for its inventor, George Dicker (1913–1989) of Tustin, California, and received a patent in 1973. The dicker-rod also aims to improve safety, as a 10-yard length of chain laying along the sideline can be a hazard for players. Additionally, it requires just one person to operate, rather than a three-person chain crew. However, the dicker-rod has not been widely used, and the first-down chain remains the standard.
The 2002 season was the San Diego Chargers' 33rd in the National Football League (NFL), their 43rd overall and their first under head coach Marty Schottenheimer. Their stadium, Qualcomm Stadium, hosted Super Bowl XXXVII at the end of the season, but the Chargers' failure to secure a playoff berth marked the 18th straight season that the Super Bowl did not include the team in whose region the game was being played. Their division was reduced to four teams at the start of the season, with the Seattle Seahawks moving to the NFC. Despite going into their bye week with a 6–1 record, the Chargers suffered a late-season collapse, winning just two out of their last nine games after their bye week and missing the postseason.
An official in Canadian football is a person who has responsibility in enforcing the rules and maintaining the order of the game, like their counterparts in the American game. In the Canadian Football League, seven officials operate on the field. Lower levels of play up to the university level use less than the standard seven.
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.
American football, referred to simply as football in the United States and Canada and also known as gridiron football, is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with possession of the oval-shaped football, attempts to advance down the field by running with the ball or throwing it, while the defense, the team without possession of the ball, aims to stop the offense's advance and to take control of the ball for themselves. The offense must advance at least ten yards in four downs or plays; if they fail, they turn over the football to the defense, but if they succeed, they are given a new set of four downs to continue the drive. Points are scored primarily by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of the game wins.
In gridiron football, a penalty is a sanction assessed against a team for a violation of the rules, called a foul. Officials initially signal penalties by tossing a bright yellow colored penalty flag onto the field toward or at the spot of a foul.
In gridiron 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.
Rule 1, Section 5: Chain Crew and Ball Boys/Girls