A common term used to describe the officials responsible for manning the chains that are used to show the ten yard distance needed to obtain a new set of downs. The chain gang is required to quickly realign the chains whenever the offense gets a first down. The chain gang may also be called upon to come onto the field for a measurement whenever the officials are unsure as to whether a first down has been achieved or not.
The chain gang is one of the important background groups in the effective officiating of a football game. They must quickly move to align the chains in a new location whenever a first down has been achieved, and must be able to accurately place the chains so that the first down distances can be accurately measured. There is a set of chains on each side of the field, although only one of the chains will be considered official for the purposes of on-field measurements.