The 4-3 Over puts it’s 3-technique or B-gap player to the strength of the offensive formation. As a result, the 1-technique or shade is to the open, or weak side, of the formation. The alignment of the front helps keep the strongside linebacker clean to make plays.
Why Use the 4-3 Over
The 4-3 Over matches strength with strength by shifting its defensive alignment. That alignment occupies more blockers at the point of attack if the offense runs strong. The 4-3 Over also allows the Mike linebacker to scrape more easily and fill gaps since the offensive linemen over him are occupied by defensive linemen.
How to identify the 4-3 Over
The 4-3 Over has the 3-technique to the offensive strength. The defensive end to the strength aligns head up or outside of the tight end. On the weak side, there is typically a 1- or 2-technique and an end aligned in a 5-technique. That leaves the Will to fill in the weak B-gap, the Mike to plug the strong A-gap, and the Sam to fill the strong C-gap if there is a tight end.
Strengths of the 4-3 Over
Shifts players to the formation to prevent strongside runs
By alignment, the 4-3 Over is attempting to stop strongside runs. It shifts the defense to the strength and allows them to shoot gaps and play aggressive to the run.
Weaknesses of the 4-3 Over
Will linebacker can be exposed on backside
With the Mike aligned and protected to the strength of the formation, that leaves the Will linebacker isolated on the weakside in the B-gap. Will linebackers are usually more athletic and slightly smaller, which can be a problem for run defense. As a result, offenses may look to run weak and attack that player.
To counter that, some defenses flip their Mike and Will players to help protect the Will in the run game and allow the Mike to fill the weakside B-gap.
The 4-3 Over aligns the strength of the defense to the strength of the offense. That allows the Mike linebacker to stay clean and make plays in the run game.