The origins of the Iso (Isolation) Play began in the 1940s, with Tom Nugent who modified the T-Formation play in football. Instead of having the halfbacks on either side of the fullback, he adjusted the play to have the fullback and the halfbacks in a line. It spread from a college football formation to a common play in the NFL even today.
The isolation play is and versatile and dominant offensive play that balances both running and passing. An isolation play is a downfield play that few defensive fronts can combat. There are various forms of isolation plays, but let's begin with the basics. The iso play can be run through the 1 or 2 hole, either side of the center, or off the 3 or 4 hole based upon who is running the play.
The term isolation comes from the fact that the fullback is directing the running back through the hole, whilst also blocking the MIKE. This play does not aim to take down several yards, but if used correctly it can achieve decent amounts of yards quickly.
There are several versions of the Iso Play, and it is adjusted depending on the circumstances of the game at hand and which player can execute the play the best. But, it's important to note that the fullback is one of the most integral pieces for the Isolation. If the fullback cannot use the isolation block, the play is ineffective. While the Iso play is a dominant offensive formation, it has to be used in moderation at the most opportune times.
This play is very effective and will have one of two outcomes: either the offense will manage to gain 4 yards or it will make the defense secure the line of scrimmage for run support. The defense is highly susceptible to Iso plays, as it is a full force play.