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MHR University - Modern 3-4 Defense Systems

MHR University Welcome to another edition of MHR University!

Today we'll look at the modern systems run in the 3-4 defense. We'll also clear up some common misperceptions about the formation, as well as look at the strengths and weaknesses of each sytem, and prefered player types.

Over the next couple of days I will be moving archived University posts into the MHR University section. This means that if you want to look up older editions, you need only go to the left panel on the main page and click "MHR University".

Read the rest of the story below the fold...

What is the 3-4?

In the 3-4, there are three defensive linemen on the field (DLs). We call the centermost DL a nose tackle (NT) and the other two defensive ends (DEs).

We also have 4 linebackers (LBs). The centermost 2 are called inside linebackers (ILBs) and the outer two are called outside linebackers (OLBs).

In the 4-3 we call the LBs nicknames, based on position, from weakside to strong side "WILL, MIKE, SAM" (for strong, middle, weak). But in the 3-4 they are named (in the same order weak to strong) JACK, WILL, MIKE, and SAM.

Advantages include -

  • It is easier to obtain quality LBs than qualtiy DLs, and thus easier to build a 3-4.
  • More "pure athletes" or on the field, since many would consider a LB to be more skilled than a DL.
  • Increased reaction time for LBs. The LBs start further back than they would in a 4-3, so they have nearly .5 to a full second to read a play as it develops.
  • Puts more men in the short zones to disrupt passes.
  • Allows for a much larger play book, as LBs have more play uses than DLs. This also means more flexibility for the defense.
  • Stops runs to the outside (wider spaced OLBs).

Disadvantages include -

  • It is not as effective against the inside running game as the 4-3, and most of the League is "run first" and runs the middle.
  • More often than not, a 3-4 can be more expensive to field (comparing the cost of LBs to DLs).

On first glance it would appear that there are more advantages, but this is offset by the glaring disadvantage against the run relative to the 4-3.

So is the 3-4 a "coach driven" scheme, or is it based on personnel?

The truth is, any defensive coordinator can run a 4-3 or 3-4 indifferently. While coaches have preferences, they more often defer to what they have available. If the team could go either way, the coordinator is probably going with what he is more comfortable with.

What's better, the 3-4 or 4-3?

Don't get in the mind set of "better" when thinking about formations and systems. They are different, and do different things. While some formations and some systems are great match-ups against other formations or systems, the rule of thumb is that the team that executes their own program better than the other team executes theirs is going to prevail.

Do 3-4 teams have seperate systems than 4-3 teams?

Yes and no. Some systems can be run regardless of system. The "Cover Two" systems can be run in a 3-4, but none are currently. The "Zone Blitz" system is a system run by both the Steelers and a few 4-3 teams.

The "Bullough" variation of the "Fairbanks 3-4" is the system being used (most notably) to great effect by NE. No team has returned to the original Fairbanks, and the classic 3-4 system is now just called "Fairbanks-Bullough". It is strictly a 3-4 system, as is the "Phillips" 3-4.

What are the systems being used by today's 3-4s, and how do they work?

There are three systems being run out of the 3-4s.

  1. The Fairbanks-Bullough (we'll call it the Bullough).
  2. The Phillips
  3. The Lebeau Zone-Blitz

The Bullough

This system is what most people think of when they think of the 3-4. It is based on 2-gap play on the D-line.

The system was used in colleges for years before, but came to the pros in 1974 and was built to withstand professional offenses by Coach Fairbanks. He coached Oklahoma (where the system was created in the 40s), and the Patriots.

Coach Bullough (who was a head coach for BUF but the defensive coordiantor for NE in the 70s) refined the system further. It no longer looks like the collegiate 3-4 of the 40s and 50s (in which the 3-4 was close to the line, every player was a brute, and the team played mostly zone).

The NT is a 2 gap player who lines up at 0 or 1 technique. The DEs will be aligned based on situation, play, and match-up. All three players are typically bigger than in the other two systems. They often plug up the OL to allow the LBs to make the big plays, and so they get little credit in the stats themselves.

One common tactic is to shift over or under (depending on the direction of the shift). Most 4-3 do this on the DL on a few plays. But in the 3-4 as run under the Bullough, the team will often "scissor", which means they shift the DLs one way, and the LBs another.

Here's a scissor:


This gives the OL little time to react to a new formation. Is the JACK LB going to "cheat forward" and play like a one gap DE, or is he going to zone? Note how the NT can now draw double coverage from the Right Guard and the Right Tackle, and the Left End (The right most "X") is still there to cause problems for the Right Tackle. The SAM LB is now in an ideal position to wrap around the line and take out the QB.

The confusion doesn't stop here. The LBs can zone, man, or blitz. That's three things that each of four LBs can do. Do the math to try to predict the number of variations. Then, before patting yourself on the back, consider that each of those actions have further variations. Man - which man? Zone - zone where? Blitz - through which lane?

Despite the fact that the Bullough can be confusing, the system relies on a lot of "bend; don't break" thinking. The system will often give up short yards in the run, and blitzes are not common. The idea is that the longer the offense is on the clock, the longer it takes them to score, and the more plays the offense risks an interception, fumble, or a fourth down.

The "Phillips"

This system is not what people think of when they think of the 3-4, because the original 3-4 was/is strictly a 2-gap system.

In fact, look at the Denver "Orange Crush Defense" of the late 70's. It was run by Red Miller, and one of his assistants at the time was Coach Belichick. Belichick ended up in NE as we all know, while Fairbanks returned to college coaching in Colorado. Denver fans would thus be more likely than many fans to think of the 3-4 in terms of 2 gap, but you can still read the mistaken notion in many sports sites and publications.

The Phillips is named after "Bum Phillips", father of DAL head coach Wade Phillips, who formerly coached the Broncos as both a head coach and defensive coordinator. Bum learned under Paul "Bear" Bryant at A&M and had coached high school football well enough to break into the college ranks (not a common route). He was a defensive coordinator in SD, then in HOU (that's the Oilers for you young folks). He later was a head coach in HOU and later for NO.

Phillips was an innovator who turned the 3-4 upside down. His system is one-gap. The DL penetrates, and is charged with constant harrasment of the QB. The LBs are typically fast, and at least one of them will blitz on any given play.

The reason for the near constant 1-LB blitz is to account for the fact that the outnumbered DL is also relatively undersized and only one-gapping. However, the adjustments work out well. The OL never knows who the blitzer will be, or where he will come from. The Phillips is more aggressive that the Bullough. The school of thought for the Phillips 3-4 is the need to pressure against the QB to stop the pass threat, and this is done by varying who the "fourth rusher" (who is really a blitzer) is.

Add another blitzer in here and there, and the speedy/aggressive Phillips system is a threat to QBs, and attempts to get turnovers by slashing the time that a QB has to make decisions.

This is the system of choice for DAL, but also SD.

It is not the ideal system for SD in one sense. Denver (king of the offensive "zone block " system for runs) and oakland (newly switched to the zone block) are built to run over the 1 gap defenses, and they share the division with SD. SD adjusts for this by:

  • Relying on a high tempo offense featuring LT, Gates, and Chambers to dictate games,
  • Backing up the LBs to give them more reactionary distance, and
  • Shooting for a better record against the Chiefs (2 games) and the other 10 games out of division.

The Lebeau zone blitz

Attack, Attack, Attack.

The Zone Blitz is very nasty thing to deal with. In terms of player types, one can vary the NT type and even the DEs, but 1 gap speed DEs are much more common.

The zone blitz play (also know as a zone fire play) has been around for ages. Dick Lebeau took the play and turned it into a full system for Pittsburgh in the early 90's. He tried his hand at head coaching and being a coordinator elsewhere, but with little success. He doesn't seem to be a good manager, and isn't great at adopting to the existing systems of other teams. What Lebeau is know for it two things. His players love him (they play hard for him), and he is an excellent theoretician who develops elaborate plays with many twists.

The idea is that the different DLs will often drop back into coverage, while several linebackers (and even defensive backs) will blitz. The OL can't brace themselves, because if they do they will likely brace for the wrong assault. This is the one defense that prides itsself on turning the tables - the defensive line and the LBs hit the OL hard and often and try to wear down the other side.

CBs most often jam or jack the WRs , then either drop into zone or blitz. SAFs either zone or blitz (a safety blitz is called a "monster"), the LBs blitz most often, and sometimes zone, the DL either rushes or ends up in zone. It's a very fun defense to watch.

This defense tries to stop the run by penetrating the OL and disrupting the offense's backfield. They stop the pass by targetting the QB with heavy blitz packages.

Here's an example of a play:


The CBs will jam then zone. The FS goes deep center zone. The NT takes his left A-Gap and tries to draw double coverage. The R-DE takes a zone typically occupied by the JACK LB, while the L-DE zones left to watch for the screen (note that screens are not effective against zone blitz schemes). The SS gets sent on a monster blitz, the JACK and SAM blitz the outside, the WILL blitzes the right B-Gap, the MIKE the left B-Gap (keep in mind that "left" and "right" are from the defense's view when talking about the defense).

It looks like a good enough play, but here's the catch. Look at the diagram again and look at the gaps. It is reasonable to assume that half of the offensive linemen are firing out of their stances and blocking someone who isn't there. They never know if the DL is coming or not. Whenever they guess wrong they get physically punished, and probably leave a trail to the QB in the meantime.

The zone blitz is very effective against screen passes, wreaks havoc against check offs by QBs (because the zones can't be anticipated, nor can the rush), and is the only major defensive scheme that is predicated on wearing down the OL instead of the OL wearing down the DL. FOr these reasons, the timing system used by Peyton Manning of the Colts can face more troubles here than in many other systems.

There is one glaring weakness. You drop a DL into a zone and the blitz doesn't hurry the QB and the QB has a quick-realease for an arm... well your defensive lineman isn't probably going to match a WR or TE going for a reception, is he?

OK, the 3-4 systems sound cool. How are they stopped?

There are many traits shared by the systems that make them vulnerable. Of course a coach makes adjustments based on personnel and film, but here are the common, over arching approaches offenses take.

  1. Two TE sets - the 3-4 killer. Take out the FB and add a second TE. The common outside blitzes by the Phillips and the Lebeau are rendered less effective. This is the most common approach, and great blockers like DEN TE Graham are perfect for this.
  2. Run the ball, run it up the middle, and run it with power.
  3. Skip the sceens and use both the FB and HB as pass blockers. Vary the TE frequently between pass blocking and receiving (throw some confusion back at the 3-4). Keep passes up the sideline, where you don't burn the clock so much, and where the zones are less frequent.


I hope you've picked up a little about the 3-4s. A lot of teams run the formation, and teams can start running it with little notice (like, right at the start of the season). Keep in mind that all 4-3 teams have a few plays they'll run with a 3-4 here and there. 3-4 teams also frequently disguise plays by lining up in a 4-3 looking formation where "extra DL" is either going to play like a DL, or play like a LB in a shifted 3-4 (this is pretty common).

As always, please feel free to ask questions in the comments section about the 3-4, or any other football related questions. If I can't help you, we have the sharpest members on the internet to help. No question is too simple either.

Next week I'll have an article about youth coaching, from city league grade schoolers to middle school to high school.

Take care!