The I Formation is one of the most utilized formations in professional football. Most commonly used in running situations, the name of the I Formation stems from the fact that the backs line up directly behind the quarterback, thus giving it a distinctive vertical look.
I Formation Tailback
The tailback is positioned anywhere from six to eight yards behind the line of scrimmage. This allows him to survey the defense and look for weak points to attack. The fullback will usually block for the halfback, but he may also head to the opposite side of the field on a misdirection play.
A pass play can also be run from the I, and the formation can accommodate up to three wide receivers (although the running back can also be used in that capacity). In this case, instead of serving as a lead blocker for the halfback, the fullback will usually stay back as a pass blocker. The formation is also useful when attempting to run the play action pass.
The "Offset I" is when the fullback lines up to the side of the line running between the quarterback and tailback, usually towards the strong side of the offense (the side the tight end is on, and therefore where more blockers are found).
Variations of the I Formation include:
The I formation was first created by Tom Nugent, coach of the Virginia Military Institute, in 1954. Intended as a replacement for the single wing formation, the I Formation caught on quickly. By 1962, USC had already won a national title using the formation, and it would soon find popularity in the professional ranks.