3-4 1 gap vs 2 gap 3-4 (1 Viewer)


Oct 27, 2006
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Complete article (MOD EDIT) Please log to read the whole thing, we can only post a teaser...


The 3-4 Defense: A Primer

I am writing this piece in response to some of the announcers and writers out there that obviously wouldn't know the difference between a 3-4 defense and a punt formation. And there might be some fans out there that do not know when they are seeing a 3-4 or a 4-3 or what the differences are. To some it might seem redundant and to others informative.

As always, I write with out the benefit of a proofer, so please ignore typos, etc.

Unfortunately, I cannot (or don't know how to) include diagrams. If some of it might seem confusing in reading I suggest the following: diagram out a typical offensive formation or offensive line. Mark the gaps as A, B, C, D with the center-guard gap being the "A", the guard-tackle the "B", the tackle-tight end being the "C", outside of the tight end is the "D". To designate the "techniques" (where the players align in opposition to the offensive line), start with the center as "0", his outside shoulder is "1", the gap between center-guard is "2", the inside shoulder of the guard is "3", and so on. Adding a "0" to any of these numbers would indicate a LB lining up off the line of scrimmage. I hope that this helps. In addition, and excellent resource (with diagrams) can be found at FOOTBALL OUTSIDERS: Innovative Statistics, Intelligent Analysis | Defensive Line Basics: Mind the Gap


The 3-4 might seem like a recent innovation. In fact, it has been around for a relatively long time. The system had been in use on the collegiate level since the 40's (Oklahoma is credited with its first use), but the defense looked vastly different as it was played very close to the line and every player was a brute. In 1970, in Superbowl IV, Hank Stramm wanted to utilize the strength of Curly Culp, a defensive lineman that was very strong and couldn't be blocked one-on-one. Stramm wanted Culp to tie up the Vikings All-Pro center Mick Tinglehoff and tie up additional guard support. He wanted to prevent the Vikings outstanding line from being able to pull and lead the great Vikings outside rushing attack. This worked out pretty well for the Chiefs as they dominated the heavily favored Vikings by holding them to just 67-yards rushing, 3 picks, and recovering 2 fumbles.

Early innovators of the defense on the professional level were Coaches Bum Phillips, Chuck Fairbanks and Hank Bullough. Today, the most familiar 3-4 with 2-gap line technique (we will get to that later) is referred to as the Fairbanks-Bullough.

In the 80's, the success of the 49ers and Cowboys with the 4-3 alignment saw most of the other teams adopt it as their base defense. However, the recent success of the New England Patriots, utilizing the 3-4, has given new life to the 3-4 in the professional football level. "It's not so much that teams are changing," said coach Bill Parcells, who won his first Super Bowl title in 1991 using the 3-4. "It's the people that have become decision makers have backgrounds in that defense and that is what they are implementing." Patriots coach Bill Belichick first learned the 3-4 while working under Parcells. Browns coach Romeo Crennel, New England's former defensive coordinator, was an assistant on the same Giants staff. Nick Saban also worked with Belichick ... and on down the coaching tree.

So why the switch to the 3-4?

Proponents suggest it's most effective in combating today's sophisticated passing attacks, with their multiple formations and intricate routes, because a fourth linebacker allows a defense the luxury of disguising its blitzes and coverages better.

If the offensive guards are responsible for blocking the inside linebackers, the center has the nose tackle and the offensive tackles are designated to block the defensive ends, who's got the two outside linebackers? And where are they?

The 3-4 also can morph into a 4-3 in the blink of an eye. The 3-4's outside linebacker can quickly come up to the line of scrimmage, drop his hand down, and voila, 4-3. Or he can stay on the edge as a decoy, pick up a running back in the flat or cover the tight end.

"I'm not saying it's better," Parcells said. "Here's what I think some of the advantages are: At any time you can drop eight people into coverage, and that complicates things for the quarterback. Not many four-man line teams have the ability to do that.

"The second thing is it's more 1-on-1 football. It forces the offense to block more straight and use less angles than a gap defense does. Sometimes that's more difficult for the offense to do."

In the 4-3 defense, you need two very large and athletic defensive tackles and two somewhat large and very athletic defensive ends. These guys are very hard to find. If you can't find a couple of good defensive ends, you're in for a long season of living and dying by the blitz.

In the 3-4 defense, you need one really large nose tackle. This NT has to be a real monster of a guy, 350 pounds or so, because his job is to take on the center and one of the guards simultaneously on every single play. Then you get two more defensive tackles at around 300 pounds each, and play them up against the offensive tackles. All three of the defensive tackles have what is called a gap responsibility. They are expected to hit the offensive linemen head on, and watch the play to make sure the running back doesn't come through on either side of them. Also, they're expected to hold their block so that the offensive linemen can't get out and block a linebacker.

In the 3-4 system, the linebackers are expected to make most of the plays. In the 3-4 system, the DTs play a more physical game as they are taking on one or two offensive linemen directly, play after play. Unlike the DTs in the 4-3, the DTs in the 3-4 are responsible for every single gap in the offensive line. Although the DTs get relatively few chances to make tackles or sack the quarterback, anything bad that happens is still ultimately their fault.

In the 3-4, you have four linebackers. Two of these guys are inside linebackers, and are expected to weigh roughly 240 pounds and be quite athletic. You also have two outside linebackers. These guys are sometimes called "tweeners," as they are in between the normal size of defensive ends and linebackers. These guys should weigh perhaps 255-265 pounds and also be quite athletic. Because these are linebackers, they tend to be faster than the heavier defensive ends. Their presence makes it much more difficult for the quarterback to roll out, as he will be rolling out directly into the path of one of these linebackers.


The 3-4 is composed of 3 down lineman, 4 linebackers and 4 defensive backs.

The defensive line positions are 2 defensive tackles and 1 noseguard. Typically, the noseguard (NG) plays head-up on the center (OC). This known as the "0" technique. The defensive tackles (DT) line up just off the outside shoulder of the offensive tackle (OT) in what is known as the the "3" technique. The primary function of the DL is to protect the LBs and play the run. Each defensive lineman is responsible for 1 or 2 gaps, depending on the scheme being used.

NG is the toughest position to fill. The NG is head-up on the OC and is responsible for defending both "A" gaps ("A" gap is the gap between the OC and OG's. "B" gap is between OG and OT. "C" gap is between OT and TE.) in the running game. He faces constant double-teams and takes a pounding. He must have size, mental and physical toughness, stamina, durability, lateral quickness, and good technique in terms of playing with leverage. If the NT cannot hold his ground, the defense is very vulnerable to runs between the tackles.

DTs tend to weigh around 290-310, and many are former 4-3 DT/DE "tweeners". They must be able to play the run well. The 3-4 DT is responsible for the "B" and "C" gaps in the running game and lines up in either the "3" or "5" technique (head-up on the OT) position. It's tough for a 3-4 DE to pick up as many sacks as a 4-3 DE, because a 3-4 DE doesn't have the freedom to go willy nilly upfield. He has to protect the LBs in order for the 3-4 to work.

The inside linebackers must be stout in run support. Because there are only 3 DL to match up against 5 OL, they must be able to stack and shed an unblocked offensive lineman in the running game. The left inside linebacker is called the “MIKE" linebacker (keep in mind that different teams might use different nomenclature for the different positions). He closely resembles his counterpart in the 4-3 except that he aligns himself in a “2" technique over the guard to the tight end side. The right inside linebacker, referred to as the “MAC" Linebacker also aligns himself in a “2" technique except he is on the “weak side” away from the tight end. In the 3-4’s most basic form both the “MIKE” and “MAC” linebackers have “A" and "B" gap responsibility, so like the middle linebacker of the 4-3 they must play the run from the inside out. However, in many of the 3-4 scheme’s seen today you see the “MAC" backer playing more of a weak side linebackers role and the “MIKE” can likewise find himself in the strong side role. The strong-side "MIKE", must have an attacking style of play to come up and meet a ball carrier at the line of scrimmage and be fast enough to string him out to the sideline. Though his first priority would be to stand the blocking back up in the hole yet plugging another running lane.The weak-side "MAC", is responsible for backside pursuit and must be disciplined enough not to overrun a play which could result in a big gain. Both players also must be able to blitz the QB and be able to drop into short zone depending on the defense called. Personnel wise the inside linebackers in the 3-4 are usually the prototypical linebacker that runs a 4.5 to 4.7 in the forty and stands 6’ to 6’4”tall at 240-255lbs. Most linebackers that play inside in a 3-4 scheme can usually translate well to the middle and weak side linebacking positions in a 4-3.

The two outside linebackers of the 3-4 defense have very similar jobs, especially in the very basic concept of the defense. An OLB in this defense is simply stated, the pass rusher. Both the “SAM” (strong-side) and “WILL” (weak-side) of the 3-4 will usually have “D gap” responsibility and will line up outside of the DE as a 5/7 technique (outside shoulder of either OT or TE). He is the guy who chases down the QB. His ideal frame is tall in the 6'4" range and normally anwhere from 240-260 lbs. Long arms are needed to disengage from NFL offensive tackles in the run game and also used in pass rush. They must be very fast as to be able to beat a Tackle to the corner in pass rush but also strong and athletic enough to utilize bull rush moves when needed. This player is also responsible for outside contain in the run game.

When Coach Hank Stram first introduced the 3-4 to the NFL it was four legitimate linebackers playing zone defense behind three down linemen. Later on teams started replacing one of those outside linebackers with a pure pass rusher and now the most prevalent version has both outside linebackers rushing the passer from a defense that more closely resembles a 5-2. On almost every play, 1 of the OLBs will rush the QB. The OLBs can play from a 2 or 3-point stance.

A cornerback (CB) in this defense has many different responsibilities from a traditional zone coverage CB. This player needs to be very fast with good ball skills as he plays alot of man coverage due to the schemes employed, dependant on what the front 7 does. Certain packages will also ask this player to play a variety of zones. The CB also be must tough enough to help support the outside run game. Normally, due to defensive formations, these players will line up on the WR with a 5 to 7 yard cushion as to not get **** the line scrimmage and surrender a deep pass play due to the extra safety playing in the box on run support, better known as cover 3. The roles of a CB vary greatly depending the defensive playcall and responsibility of the safety.

Like a Safety (S) in any defense, they must be able to play centerfield to be successful. Due to the versatility of the defense, its common to only have one deep safety in the pass game, which is why referring back the CB's will line up with a cushion b/c there isnt alot of help there. These players make all the secondary calls and must be strong in second level run support. The free safety (FS) is responsible for reading the offensive plays and covering deep passes. Depending on the defensive call, he may also provide run support. He is positioned 10 to 15 yards behind the line of scrimmage, toward the center of the field. He provides the last line of defense against running backs and receivers who get past the linebackers and cornerbacks. He must be a quick and smart player, capable of making tackles efficiently as well as reading the play and alerting his team of game situations.

The strong safety (SS) is usually larger than the free safety and is positioned relatively close to the line of scrimmage. He is often an integral part of the run defense, but is also responsible for defending against a pass; especially against passes to the tight-ends.
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Hey, if this is from an article online, can you please link the article and just tease it?

Great read though.
We will all be 3-4 gurus by April. This is awesome. Thanks for the post bro.
Very nice indeed. Came across this article few months ago when i was contemplating the switch(i know like i had some sort of hand in this) lol.

Man im still sold on the Phillips 1 gap and the threat of never knowing which LB will rush.

OgleTree and Martez would be just godly@that. Both are capable of dropping in coverage and both are capable of shooting a gap on a blitz.

I like thee idea of line stunts too.

The ability to bracket coverage also appeals to me.

I think this is what SF does a lot of especially with the 2 deep man under. Those guys just sit on all our short routes and they are alwys hitting the beegesus out of us.

Man im stoked. Good post/read.
3-4 LB's.....see "Dome Patrol". We need another 57, who needed no learning curve, just came out of Pitt and launched himself toward Canton.

Another thing I didn't know about Hank Stram. He was a genius. And a fraternity brother of D. Brees.
You know they says that it's the defensive ends that make a 4-3 work but I think its the 3-Tech DT that makes the difference and the Saints haven't had one since LeRoi Glover was being misused in a primarily 2-gap defense.

Withhout having that quick defensive tackle that can get in the backfield, disrupt plays and make offenes change to scheme for him, I think our personnel are better suited for the 3-4. It gets more athletes on the field.
Is this Lebeau's philosophy too? Seems like this is the big advantage of the 3-4. You've essentially got a zone blitz on every play even if you just rush 4.

Lebeaus is very very very very zone heavy....but it also requires 2 gapping still.

The Dick LeBeau 3-4

However, what i like about Grantham is he seems to be a mix of all 3. He brings zone pressures like Lebeau, 1 gaps like wade phillips, but can 2 gap and gameplan to take away the opponents best option like Crennel/Mangini believe in.

He has also seen the read option for the last few years in the SEC quite a bit.

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