AbsolutAnalysis: Defensive Fronts (Part 2)

Continuing his very popular series, Seahawks.Net's Matt Latham looks deeper into defensive fronts. This time Matt delves into 3-4 alignments and the 4-3 Stack front. More great stuff for Browns fans looking to learn more about the game within the game!

Welcome to Part 2 of the Defensive Fronts series. In case you missed it, check out last week's Part 1 column outlining Defensive Fronts and gap assignments. In this article, I will follow up by presenting a 4-3 Stack front, and a basic 3-4. I decided to make this a three-part series, and next time we will take a look back at the 46 Bear defense. Let's start this week by looking at a 4-3 Stack.

This is probably the most familiar looking defense. Four linemen and three linebackers, staggered and parallel. Sometimes this is referred to as a College 4-3, while an Over or Under front is called a Pro style 4-3. However, you will see both at each level. In fact, I remember Shaun Alexander breaking off a 44 yard run against the Cardinals while they were in a Stack front last season. From what I have seen, this is the most common High School 4-3 defense, at least in the NW. It can be a very basic and fundamental scheme, with simple alignments and gap responsibilities, easy for lower level players to understand. But of course, get to the Pro level and Ray Rhodes will have a field day with any front. One of the most attractive aspects of this front is the symmetry it presents. The DE's are lined up wide and are both outside players with leverage to always defeat the TE, while the OLB's are lined up inside the ends in a 6 alignment, capable of making plays from sideline to sideline. Having the OLB's off the line of scrimmage gives them an advantage over the tackles due to their (usually) superior athleticism, and doesn't limit them to one side of the field. Although I have the DT's lined up in threes, they will have certain alignments based on the formations the offense presents, and will change shade based on what they see.

4-3 Stack vs. Weak side run

 In its essence, versus any run this defense is very straight-forward and "makes sense." The DE's are playing wide, which makes them the obvious outside contain and primary force on an outside run. When playing a cover 3 shell, a safety may be the primary force on an outside run, but for practical purposes, the DE is. The Will must keep all blockers in front of him on his inside pad, and pinch them inside. If he should ever get hooked inside, the defense is in for a world of hurt because the ball will be bounced out into open field. He must, as is always the case, keep from getting hooked and keep the ball funneled inside where the rest of the defense is flowing from. The DT has his play side gap, which is weak B gap for the Weak DT in this case. Mike is responsible for controlling the play side A Gap (which is always the case for Mike in this front) on his way to the ball to clean up a play. Against a run to the weak side, he is assigned weak A gap on his way to the ball. The DT lined up to the strength must pinch his man down if shaded outside in a 3 (see shading alignments in last week's column), and close the strong A gap from cutback. Sam is responsible for strong B gap while getting to the ball, primarily concerned with cutback and counter. The Strong DE must trail the play while pinching C gap and containing reverse and cutback defense.

4-3 Stack vs. Strong side run

 As I'm sure you imagined, a strong side run into a 4-3 Stack is awfully similar to a weak side run. As I mentioned at the beginning of this article, symmetry is a key of this defense. The DE assignment stays the same on the play side; usually primary force, attacking the play as the first man to get there. The weak side end is the reverse\contain man while the DTs attack their gaps corresponding to the play side. Mike once again is assigned to the play side A gap, in this case Strong A, while moving to the ball. The one difference here is that the Sam must be responsible for the C gap on his way to the ball. This comes from the fact that there is no C gap on the weak side for the Will to cover, so the Sam has a bit of added responsibility on his shoulder when the ball is ran at him.

Basic 3-4

Here's a defense that has often been discussed in the .NET members forum; switching from a 4-3 to a 3-4 due to our fairly deep talent at linebacker, and the shortage of quality DT depth. However, I think with the emergence of Moore, Woodard, and the drafting of Tubbs, that has quieted down a bit. Although I must confess, I'd love to see DD Lewis as a full time player for us. Anyway, on to the 3-4. While maintaining seven men in the box, this front is characterized by 3 linemen and 4 linebackers. The relationship between alignments and responsibilities of the DL are a bit different than a 4-3. The NT is in a head-up 0, meaning he is lined up directly over the Center. This also means that he is a "two gap" player; he must control both A gaps, regardless of where the ball is run. He needs to be a solid, strong player capable of sticking the Center and standing him up so that he doesn't get hooked, and is able to attack either gap on any play. The DEs are either one or two gap players, depending on their alignment. If they are in a 6 shade, then they are one gap players, responsible for C gap on plays attacking their side of the formation, while pinching down the B gap with the Tackle on plays to the away side. However, if the DE is in a 5, they become two gap players, assigned to the C gap on plays to their side, and are responsible for getting themselves to the B gap on plays away from them. Either way, they must be capable of knocking a Tackle onto his heels and turning his shoulders while controlling two gaps. This is vital because it allows the LB behind him to play with proper angles to get to the ball.

3-4 vs. Weak side run

The 3-4 is well suited to defend a weak side run, as they have 4 players against 3 offensive linemen, plus a strong side ILB that is capable of crossing into that half with a few steps towards the ball. For the sake of this column, I will assume that the DEs are lined up in a 5. Versus a weak side run, the Nose gap sticks the Center and moves into the weak A gap, while the strong DE stands up the Tackle and moves himself into the B gap when he sees an away side run. The weak DE must control the C gap on this play, as the weak ILB takes B gap (to C gap on wide plays). Strong side ILB must defend the A gap against cutback on his way to the ball, and the SOLB is responsible for reverse while trailing the play.

3-4 vs. Strong side run

What do you know...symmetry! Runs to the Strong side are pretty much identical to the Weak, since each half of the box is nearly identical. Strange considering it contains an odd number of players. But that is where having a stud at NT who is capable of control two gaps comes in useful, and essential. This front is actually capable of being more symmetrical then a Stack, since the whole DL can be aligned to be two gap players, and the two ILBs help create post-snap mismatches as they can quickly enter the play side of the box from the backside once the play begins

That does it for this installment of the series. Stay tuned for Part 3, which will include the 46 Bear defense, as well as some other information which is as of yet undecided.

Matt Lathrop, .NET's "Xs and Os Guru", has been contributing his articles Feel free to contact him at mattl@seahawks.net.

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