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View Full Version : The 4-3 vs. the 3-4



Denver Native (Carol)
02-24-2009, 05:36 PM
As we have heard that the Broncos will now play more 3-4 than 4-3 - found this article explaining the difference between the two:

The Base 4-3

In a standard 4-3 defense, the line consists of two tackles and two ends. Where exactly they line up depends on the coach, the play, and the situation. But generally, the tackles take on the opposing guard and center, while the ends attack the opposing tackles and tight end.

What happens at the snap depends on the play and the philosophy of the coach. There are two basic responsibilities for defensive linemen: one-gap and two-gap. When playing one gap, the lineman attacks a space between two blockers. For example, one of the defensive tackles may try to penetrate the line by attacking the space between the right guard and right tackle. The defender is only responsible for what happens in that hole. When playing two-gap, the lineman engages his blocker, reads the play, and takes responsibility for anything that happens to his left or right. The same defender from the last example, playing two-gap, might engage the right guard head on. Once he knows how the play is developing, he'll know whether he has to move to the left or to the right to make a tackle or chase a play.

Whether they're playing one-gap or two-gap, the defensive linemen want to disrupt the blocking scheme and occupy offensive linemen. That frees the three linebackers to make tackles. Like the linemen, linebackers often have gap responsibilities. But when the four defensive linemen have forced all five offensive linemen to block them, the linebackers have it relatively easy: they only have to worry about the fullback and/or tight end getting out to block them, not a 320-pound guard.

On passing plays, the four linemen attempt to sack the quarterback in most situations. Again, the four-on-five mathematics is critical. Ideally, with defensive ends using their speed and tackles using their power, the defensive line will be so effective that all five offensive linemen will be needed to block them, and even then the quarterback will be in jeopardy. The defensive coordinator then has lots of options: he can send a linebacker or two on a blitz, knowing there is no one to block them, or he can commit the linebacker to coverage, knowing that the line will still be able to get pressure.

The one- or two-gap scheme is a gross oversimplification. Linemen can have many other responsibilities. They can slant, moving laterally to engage a blocker to the left or right of the one facing them. They can stunt or twist, wrapping around one another to confuse the blockers. Coordinators can create all sorts of variations from a base 4-3 front, but the goals are generally the same: disrupt blocking patterns, take away running lanes, harass quarterbacks.

In terms of personnel, the ideal 4-3 defensive tackle weighs close to 300 pounds but is quick-footed enough to shoot through a gap at the snap. Ends are lighter and quicker. Right ends, who line up against the offensive left tackle and attack the quarterback from the blind side, are usually the best athletes on the line: 275-pound monsters with incredible quickness and agility who can outflank blockers who are bigger and heavier. The middle linebacker in a 4-3 scheme must be as smart as he is athletic; his assignment on any given play may change from pursuing a running back to dropping into zone coverage, depending on what the offense does at the snap. The outside linebackers must be fast enough to chase ballcarriers from one side of the field to the other, and must also be big enough to do battle with an offensive lineman.

The Base 3-4

The key player in a 3-4 scheme is the lone interior lineman, who is usually called the nose guard or nose tackle. He lines up directly across from the center � on the center's "nose" � though he may sometimes shade over to the space between the center and one of the guards. He almost always has two-gap responsibility. His job on nearly every play: force two offensive linemen or more to block him.

The defensive ends in a 3-4 alignment have jobs similar to that of the nose tackle: they want to take up space, fill gaps, and occupy blockers. In a 4-3 system, linemen are supposed to occupy blockers, but they are also expected to free themselves to make tackles and sacks. In the 3-4, linemen aren't expect to make many sacks or tackles. Most of the playmaking responsibilities fall upon the linebackers.

The 3-4 system gives the defensive coordinator a variety of options. At the snap, he can blitz any combination of linebackers, and the offense doesn't necessarily know where the rush is coming from. Typically, one or both of the outside linebackers will attack the line of scrimmage, whether to pressure the quarterback or tackle a running back in the backfield. That leaves two inside linebackers to follow the flow of the play, pursue running backs, or drop into pass coverage.

The 3-4 alignment is popular now because it allows defenses to zone blitz effectively. The "zone blitz" is just what it sounds like: some defenders blitz, the rest drop into zone coverage. In a 4-3 system, zone blitzing is tricky: the linebacker or safety who blitzes leaves a zone unoccupied. Another player can take over in the unoccupied zone, but a) that defender is stretched pretty thin, with an extra-large zone to defend, and b) the quarterback can usually see what's happening. Many a smart quarterback has defeated a zone blitz by waiting for a linebacker to attack, then dropping a soft pass into the part of the field that the linebacker usually defends. But with an extra linebacker on the field, the defensive coordinator has more flexibility. The faster linebackers can rotate quickly at the snap of the ball, filling each other's zones.

Say the coach wants both the left outside and middle linebacker to blitz. Normally, that would leave a big space on the left side of the field, one the offense could exploit with a quick slant pass. But in the 3-4 alignment, there's an extra inside linebacker who can quickly slide into that unoccupied zone. The right outside linebacker can move over to cover the middle of the field. The zones are a little wide, and the defenders in coverage have a lot of space to defend, but the quarterback must assemble a jigsaw puzzle to figure out who's where, all the while bracing for the blitz.

The nose guard in a 3-4 system must be huge, strong, and have incredible stamina: he takes on two blockers per play, every play. Ends must also be bigger and more durable than the ends in a 4-3 scheme, though they don't have to be as fast. Pass rush responsibilities are handed to the outside linebackers, who are expected to be lightning-quick runners and ferocious hitters. The inside linebackers in a 3-4, like middle linebackers in the 4-3, have to be smart, athletic, and versatile.

Variations

The base alignments explained above are very broad outlines. In modern football, there are hundreds of variations of each base set.

For some teams, the 3-4 and 4-3 are almost interchangeable. The right end in a 4-3 may be a 255-pound defender who sometimes drops into coverage: how different is he from an outside linebacker? Or, the outside linebacker in a 3-4 may line up in a three-point stance on the line of scrimmage for much of the game: why not call him a defensive end?

Teams that want to use a standard 4-3 scheme often face a dilemma: there aren't enough great defensive ends to go around. Players like Julius Peppers or Jevon Kearse come along about once per year in the draft. Most college defensive ends are great athletes who weigh about 260 pounds: put them on the line against a 320-pound left tackle, and they'll be plowed under on most running plays.

Changes in offensive style have also forced evolution in defensive alignments. When an offense lines up with five wide receivers on first down, then two tight ends and two running backs on second down, what's a defense to do? It has to adjust, by using five or six defensive backs on some plays, and extra linebackers on others. The one constant is that the defense usually tries to attack the five offensive linemen with four defenders, but those defenders could be any combination of traditional tackles, ends, and linebackers.

Teams like the Steelers and Bills ran the ball so effectively last year that opponents switched to a 4-4 defense: four linemen, four linebackers. At times, the extra linebacker crept up to the line and into a three-point stance. Suddenly, the five-man defensive line had returned to the NFL, strategy coming full circle. That's the nature of the game, and that's why it's a source of endless fascination.

http://msn.foxsports.com/nfl/story/5913858/The-4-3-vs.-the-3-4

tripleoption
02-28-2009, 11:36 AM
Havent' been here for awhile. Glad to see a football 101 section here. Personally, I'm a huge fan of the 3-4, which is often called a '50' front in football circles. As a high school coach, I've always liked the flexibility it gives me, plus I only need three down linemen, and when you take what you get, it's sometimes hard to find four down linemen.

West
02-28-2009, 07:15 PM
Havent' been here for awhile. Glad to see a football 101 section here. Personally, I'm a huge fan of the 3-4, which is often called a '50' front in football circles. As a high school coach, I've always liked the flexibility it gives me, plus I only need three down linemen, and when you take what you get, it's sometimes hard to find four down linemen.

I played in the 50 in high school. Its not quite a true 3-4 as its almost always having 4 men rushing except in Cover 8.

tripleoption
03-02-2009, 08:26 PM
I played in the 50 in high school. Its not quite a true 3-4 as its almost always having 4 men rushing except in Cover 8.

Hey west, how did you guys play your '50' front? What alignments did you use? How did you play your cover 8? Pretty much I've seen different names given to different coverages once you get past cover 3. Now I've seen coaches call a cover 4 look cover 8 but they're using the playside safety as an extra man in the box. Is this what you guys did? Look forward to chatting with you. :beer:

West
03-02-2009, 08:36 PM
Hey west, how did you guys play your '50' front? What alignments did you use? How did you play your cover 8? Pretty much I've seen different names given to different coverages once you get past cover 3. Now I've seen coaches call a cover 4 look cover 8 but they're using the playside safety as an extra man in the box. Is this what you guys did? Look forward to chatting with you. :beer:

We would shade to the strong side on the DL and the the Mike LB would play head up the weakside guard and the Sam would play outside shoulder of the strong side guard. Corners would play 5 yards off. Safeties would play 7 yards off and outside shoulder of the end man on the line.

Our base defense was "Strong Cover 4". Basically it means, DL slants to the strong side and the defense would play Cover 4 behind them.

ILB's have the hook and the OLB's have the Curl/Flat. The End would rush if a back doesn't cross his face. And if he did, he would play Curl/Flat.

Cover 8 was our prevent defense. We'd only run it in 3rd and super long and at the end of the game when the other team had no chance of winning. Basically.. DB's played deep, OLBs played Curl (left the flat open, no point to cover it. Didn't let anything get behind them), ILB's played Hook.

The only time we would roll up a safety is when we were in Cover 3. The FS would go to the middle of the field and the SS would roll up to like an extra OLB at the QB's cadence. The SS would play 4 yards off the TE or 4 yards off and split the Tackle and number 2 receiver if its twins (we would call the strength to the 2 receiver side, regardless of where the TE was)


Hope I answered everything!

Joel
04-16-2009, 04:25 AM
That's a good and often necessary overview. The big things that have always stood out to me are the personnel changes; there's more to switching from a 3-4 to a 4-3 than just having one of the OLBs in a three point stance.

The 4-3 puts more pass rushing and run responsibility on the defensive line, which is why we've heard so much in Denver the past few years about the ends just rushing the QB. Linebackers don't have to blitz as much, and "play in space" a lot more, taking care of the outside run and dealing with check down receivers while the line as a whole ensures the offense can't just run up the gut for 4 or 5 yards a carry. The keys are the defensive ends and the middle linebacker, all three of which have to be big, fast and smart. Occasionally, a DC will even get tricky and rush and extra linebacker while he pulls an end into coverage of a tight end or running back, though how well that works varies with the players and situations (I still have nightmares about Ebenezer Ekuban, a very good end, trying to cover LaDainian Tomlinson all the way down field on a 70 yard TD reception; never gonna happen....) The Mike in particular is critical, because on any given play he might have to blitz, run stuff or cover a talented receiver; he has to not only have the ability, but the prescience to know which duty is required ahead of time, frequently audibling out of the base D to react to his read on the offensive formation. In a 4-3 the MLB is the QB of the D; it's that simple, and why you need a good backup there just as badly as you need one at NT in the 3-4.

I actually prefer the 4-3 because I prefer running to passing generally, but in the era of multiple receiver formations and offenses the 3-4 has a lot to recommend it, just as it did when the AFL was legtimizing the pass oriented offensive and sounding the siren call to the 3-4 that lasted until the '80s power running teams. But the structure requires different skill sets and athletic abilities; where the ends and Mike make the 4-3, the nose tackle and outside linebackers are the core of the 3-4. Losing a defensive tackle makes it essential that the one remaining can clog the middle as well as demand double teams from the center and one of the guards; otherwise the offensive line just has too much power at the ball and the linebackers and safeties are forced to stop runs that have already picked up yards before they arrive. As noted above, that's a grueling job to do for three and a half hours a week, and most successful 3-4s will have TWO quality NTs to rotate so they don't get run over when the star is puffing on the sidelines. Meanwhile, the OLBs are in much the same role as the Mike in the 4-3; they and their coach have to know on any given down whether they should blitz, play the run at the line or cover third receivers, tight ends and/or running backs. Unless they're blitzing a good 3-4s ILBs know they mostly have to worry about the short passing game over the middle; they have safety help deep and a bruising NT to stop runs up the gut. The OLB has to do it all though, which is probably why the only Super Bowl MVP from a LOSING team was Chuck Howley, an outside linebacker in the Cowboys 3-4 when they lost to the Colts.

Make no mistake, folks, going to a 3-4 won't be a quick or easy rebuild. I've argued for it myself the past few years because it grants both an extra speed man to cover the extra receivers far more popular than twenty years ago and because it allows teams to mix up their pass rush packages; when any two (or more) of four linebackers can and will blitz on every down it keeps the offense guessing a lot more. But every time the argument was rightly made we didn't have the personnel; no huge dominating NT to anchor the line at the center and no huge but speedy OLBs to play all over the field. Indeed, I've argued for some time we should have a true NT or two in our 4-3 just because we've fared so abysmally against the run up the gut, but if you can't clog the middle with four down linemen, don't expect to do any better with three. And as much as I like D.J. Williams, I'm not sure he's got the size to be a 3-4 OLB, though I think he could excel as an ILB.

It all depends on what you've got and what you get, which is why, regardless of the short term future, I hope the new coach will get at least four years or so to remake the team in his own image. It will take time to transition the roster from guys suited to what Shanny and Co. wanted wanted to what the new coaches want, and while they have to be cognizant of the fact they don't yet have all the ideal bodies on the field and craft their playbook accordingly, every coach has an ideal picture of how they want the team to look, one that isn't going to take shape after two or three draft picks and as many trades/free agents. Fortunately for us I think Pat Bowlen's smart and experienced enough to know that, so Denver won't go the route of so many teams perpetually changing coaches every few years as each one tries to fit his predecessors players to his own system. Of course, the best coaches will fit their system to reality and maximize their players performance, but in the pros... how many coaches have won Super Bowls with multiple teams (Hint: It's <1.)

Broncolingus
04-16-2009, 08:38 AM
4-3 or 3-4, I just hope Denver gets some DL that can produce...

'Scheme' hasn't been the problem of the past (almost) decade...lack of playmakers on the DL has been.

Have I said that before?

Dean
06-15-2009, 11:24 PM
I found the URL for this analysis on what used to be Broncomania. I was impressed enough at the depth and analysis to bring it here. it is a look at teams that went from the 4-3 to the 3-4.

http://www.footballsfuture.com/phpBB2/viewtopic.php?t=328837

broncogirl7
06-16-2009, 12:00 AM
I really like the 3-4 and the element of surprise that is offers. Hopefully, we see alot of this....

lex
06-17-2009, 10:19 AM
Havent' been here for awhile. Glad to see a football 101 section here. Personally, I'm a huge fan of the 3-4, which is often called a '50' front in football circles. As a high school coach, I've always liked the flexibility it gives me, plus I only need three down linemen, and when you take what you get, it's sometimes hard to find four down linemen.

Yeah, this is not only true from a competitive standpoint but also an economic one. Defensive lineman are one of the trickiest positions to draft. Theyre expensive and it often takes a long time before you know whether or not he is any good. So, the fewer Dlinemen you have, the less of a hardship this becomes. Basically, its easier and less costly to draft linebackers than it is DLinemen.

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