Chain crew

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.

1. A "rod man" holds the "rear rod" that marks the beginning of the current set of downs.
2. Another "rod man" holds the "forward rod" ten yards toward the defense's goal-line from the rear rod. This marker indicates the line to gain, which the offense must reach in their series of four downs in order to retain possession of the ball. The two rods (sometimes known as "sticks") are attached at the bottom by a chain exactly ten yards long. The chain is always taut so that the rods are ten yards apart.
3. The "box man" holds a pole that marks the line of scrimmage.

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.

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.

On-field measurements

A first down measurement during a game between the USC Trojans and the California Golden Bears.

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.

All levels of organized football use the chain crew. One notable exception at the professional level was the World Football League of 1974 to 1975, which used the "Dicker-rod," a proprietary, 90-inch stick that allowed measurements to be made with one person instead of three. The Dicker-rod was never used outside the WFL.

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] However, further application of technology to measure the lengthwise position of the football, such as sensors inside the football, may be resisted based on affection for the human element.[1] 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] Lazser Down, a system that uses wideband radio waves to precisely spot and measure distances, has seen some rollout in college football, the Alliance of American Football and the XFL.[7]

• 2020 Official Playing Rules of the National Football League. NFL Commissioner. Retrieved November 23, 2020 – via NFL.com. Rule 1, Section 5: Chain Crew and Ball Boys/Girls
• Sherman, Rodger (December 20, 2017). "The Chain Gang Is Football's Silliest Anachronism, and We Must Protect It at All Costs". The Ringer. Retrieved February 7, 2023.