What's in a scheme? Part II -- the 4-3 defense

For the second part of this series, I want to take a look at the 4-3 defense. There are a couple reasons why I decided to do the 4-3 second, but the big one is that it is the defense that Giants fans are most used to. The Giants have run a 4-3 defense, in one form or another, for a very long time.

Like the 3-4 defense, the 4-3 traces its roots back to the 1940s as defenses had to adjust to the evolution of the forward pass. Back in those days, football defenses were all about controlling the line of scrimmage, and they used a 7-2 alignment. Once teams offenses were allowed to start throwing the ball, defenses had to adjust. One of the most successful adjustments was then Giants' head coach Steve Owen's "Umbrella Defense". That defense featured a 6-1-4 alignment, however the two defensive ends would occasionally drop back in coverage. Under defensive coordinator Tom Landry, that 6-1-4 evolved into the base 4-3, a defense he took with him when he became the head coach of the Dallas Cowboys.

Base 4-3

The base 4-3 is an even, balanced front. The four down linemen play one-gap techniques, either controlling the offensive line in run defense or shooting gaps in a pass rush. The defensive ends typically line up at the 7-technique, on the outside shoulder of the offensive tackles. On the inside of the base 4-3, both defensive tackles line up over the guards' inside shoulders.

Meanwhile, the three linebackers in a 4-3 have to be well rounded athletes, both strong enough to occasionally take on offensive linemen in run defense, but athletic enough to either drop into coverage or blitz the passer.

Ideally, the 4-3 defense will create pressure on passers, or occupy the offensive line in run defense, while the linebackers either drop into coverage to control the middle of the field, or make tackles in run defense.

Over & Under Fronts

In the base 4-3, the defensive tackles are evenly spaced, but what about when they take on specific roles, such as nose tackle and rusher?

That is where the 4-3 Over and Under fronts come in.

Both of these fronts use a nose tackle and a 3-technique.

In the Over front, the nose tackle shades to the weak side of the center, playing the 1 technique, while the other tackle plays the 3-technique on the strong side of the formation. The over is a bit more balanced front, and puts more emphasis on the strong side of the play. The 4-3 Over is generally the "basic" 4-3 employed by NFL defenses. It uses a fairly balanced line that lets the front four more easily account for run plays.

The Under formation, however, puts the 3-technique on the weak side of the offense (away from the tight end). By doing that, the Under puts much more pressure on one side of the offense. That puts a lot of pressure on the right defensive end, who might have to deal with the right tackle and tight end, as well as any run to that side. However, the Under puts a lot of stress on the left side of the defense, upping it's pass rush potential.

While the 3-4 is dependent on its nose tackle, the Under front depends on the under tackle or 3-technique. Because the Under is so aggressive, the 3-technique needs to be disruptive for the Under to work properly.

Hybrid Defenses

After decades of coaches innovating, learning from, and adapting to each other, not to mention the ever-present arms race between offenses and defenses, it was only a matter of time before the 3-4 and 4-3 defenses were recombined and a new animal was born. Probably the best example of this is Seattle's take on the 4-3 Under defense.

In the Seahawks' take on the 4-3 Under, they essentially play a 4-3 defense using 3-4 personnel. In the diagram above, you can clearly see the bones of a 3-4 defense with the 5-tech, 1-tech, and 3-tech looking very similar to a 1-gap 34 defense. And in fact Seattle uses three very large linemen for these positions.

They also blend 1 and 2-gapping principles. The 1 and 5-techniques use 2-gap principles, while the 3-technique and "LEO" (7-technique) use 1-gapping techniques. In this picture, the left half of the defense (from our perspective), is playing a 4-3 while the right half of the defense (from our perspective) is playing a 3-4.

In this defense the "LEO" is essentially an undersized defensive end or a defensive end/linebacker hybrid. The SAM is a traditional strongside linebacker, but by playing close to the line of scrimmage he can disguise whether he is blitzing or dropping back in coverage.

If the Giants' next defensive coordinator were to adopt a hybrid-style 4-3 Under defense, Hankins would obviously be the 1-technique while Jay Bromley fits nicely as the 3-technique. Although, given Hankins' quickness and what Bromley showed holding up in the run game, both could play either. Jason Pierre-Paul is a natural fit as either the 7-technique or the 5-technique, as are Robert Ayers and Kerry Wynn. Damontre Moore fits well as a LEO or as the SAM, while Devon Kennard would make an excellent SAM as well.

Final Thoughts

It seems likely right now that the when the Giants select their new defensive coordinator he will run some variation of the 4-3 defense. While the Giants have the personnel to run a 1-gap 3-4 as a wrinkle, they really are built for a 4-3 defense.

The 3-4 defense certainly has its advantages, such as how it lends itself to disguising blitzes and it is easier to find the personnel for a 3-4 defense than a 4-3 -- other than a true nose tackle, that is. Those guys are rare.

The 4-3 has its own advantages. The biggest is that a 4-3 defense puts much greater athletic demands on the defensive line. And because of that, a good line can win the battles up front despite being at a numbers disadvantage. That frees up the back seven players to either drop into coverage or blitz to add more pressure. The problem is that it is difficult to find linemen with the athleticism to rush the passer while also having the strength to make plays in run defense. It is also difficult to find well rounded linebackers for a 4-3, but because of the demands on the defensive line, resources must be spent there first.

Personally, my hope is that the Giants' next defensive coordinator use a hybrid Under formation as the base defense. Hybrid defenses offer the flexibility of a 3-4, allowing defensive coordinators to disguise pressure and play to the strengths of more varied players. However, it also takes advantage of the athleticism of 4-3 defenders.

There is no definitive way to build or run a hybrid defense, but the flexibility it gives a defense makes it enticing for a defensive coordinator to put his own stamp on, as well as freedom for front offices in drafting and signing free agents.

That's enough on the front seven players. Next time we'll be looking at coverage schemes.