In the 2009 NFL season, seven out of the top 10 teams, in both scoring defense and total defense, ran a variation of the 3-4 defense.
This article dives into the 3-4 defensive philosophy and dissects each position and its role in the scheme.
General Info on the 3-4 and The Steelers' Defense
The 3-4 defense is predicated on the ability to have multiple fronts, with the same personnel, with the intent of confusing the offense, and having the option to be flexible on any down and distance. In my opinion, no team in the NFL does this better than the Pittsburgh Steelers with their 3-4 zone blitzing scheme.
The Steelers have successfully ran the 3-4 defense since the 1982 NFL season and have fielded the top defense in the NFL five times, and have placed in the top five twelve times. Much of this success can be accredited to Dick LeBeau and the zone blitzing 3-4 variation scheme he created. But more importantly, the Steelers have always drafted the right personnel for their version of the 3-4 defense.
For those unfamiliar with the 3-4 defense, I will offer a brief description of the look of it. The 3-4 scheme utilizes three defensive linemen, consisting of a nose tackle and two run-stopping ends; four linebackers, consisting of two smaller inside linebackers and two larger outside linebackers; and four defensive backs, consisting of two corners and two safeties.
3-4 Defensive Philosophy
Today's NFL is a quarterback, pass-driven league, and defenses have been forced to adapt as a result, which is why the 3-4 has been revitalized in recent years.
The 3-4 defense has an immediate advantage over the 4-3 defense with defending the pass because of the ability to have four linebackers drop into coverage instead of three, and by having the ability to rush any combination of linebackers and defensive linemen.
With the right personnel, the 3-4 is also superior to the 4-3 in run defense by having the three defensive linemen occupy multiple blockers, giving the linebackers free lanes to hit the hole.
What truly sets the 3-4 apart from the 4-3 is the amount of versatility it gives to the defensive coordinator. For example, on 3rd-and-long, the defense could come out with its base 3-4 defense, and midway through the snap count, James Harrison or LaMarr Woodley could put their hands in the dirt and rush the passer, or they could just as easily drop into coverage.
Nose Tackle: Their job in the 3-4 defense is to occupy both the center and the guard on running downs at the point of attack and collapse the interior of the pocket on passing downs; it should be noted that nose tackle is the most vital position in a 3-4 defense because of their ability to occupy multiple linemen. The prototypical nose tackle should be the heaviest and strongest man on the field. They usually line up head-up on the center. Casey Hampton plays nose tackle for the Steelers and his mammoth size and strength have anchored this defense for many years.
Defensive End: The primary job of the defensive end in the 3-4 is to be strong at the point of attack and be able to push past double teams on running downs and not be fazed by chip blocks when rushing the passer. The ideal 3-4 end is around the size of a 4-3 defensive tackle and much stronger than 4-3 defensive ends. The defensive end usually lines up outside or head-up on the offensive tackle. Aaron Smith, one of the most underrated players in the NFL, and Brett Keisel play defensive end for the Steelers.
Inside Linebacker: Inside linebackers have to be athletic enough to drop into coverage and rush the passer, but also strong enough to shed lead blocks to get to the ball carrier. The ideal inside linebacker will be smaller but more athletic than the prototypical 4-3 middle linebacker. They will usually line up over the guards, three to four yards off the line of scrimmage. James Farrior and Lawrence Timmons play inside linebacker for the Steelers.
Outside Linebacker: The outside linebacker is the jack of all trades in the 3-4 defensive alignment, as they need to have adequate pass coverage skills and exceptional run-stopping and pass-rushing skills. The typical size of a 3-4 outside linebacker is similar to the size and athletic abilities of a 4-3 defensive end. They will usually line up outside the offensive tackles, one to three yards off the line of scrimmage. Sack masters James Harrison and LaMarr Woodley play outside linebacker for the Steelers, James Harrison won the NFL Defensive Player of the Year Award in 2008.
Cornerbacks: The role of a cornerback in a 3-4 defensive alignment is relatively the same as a cornerback in the 4-3 scheme. 3-4 corners may attempt to jam the receivers more frequently, but the role of a cornerback is dependent on the coverage that is called in. The cornerback will line up anywhere from one to five yards off the line of scrimmage on the receiver or area that they are assigned to cover. Currently Ike Taylor and William Gay play cornerback for the Steelers.
Free Safety: The secondary role of the free safety in the 3-4 is to provide run support when necessary, but their primary role is to read the offense and defend the deep half of the field from the pass. The free safety in the 3-4 will often line up 10 to 15 yards off the line of scrimmage on either side of the field. The free safety will generally use their knowledge of the game to create turnovers. Ryan Clark plays free safety for the Steelers, but it should be noted that he plays like a strong safety with his aggressive style.
Strong Safety: The role of the strong safety in the 3-4 is to provide the big hit on receivers crossing the middle of the field, be able to adequately defend against the pass, and play in the box on running downs. The prototypical strong safety in the 3-4 is a very fast, hard hitter with the body of an undersized 4-3 linebacker. They will usually line up five to 10 yards off the line of scrimmage on either side of the field. Troy Polamalu, one of the best defensive players in the NFL, plays strong safety for the Steelers.
Note to the Reader
If anyone has any questions about the 3-4, please post them in the comments below, and I will answer them to the best of my ability.