Football has many different defensive fronts and structures. Each coach has their own philosophy on which defense they should play. Most of the defenses in football are predicated on personnel as well. If the coach has the right personnel for his scheme, then they can stop both the run and the pass.
In this article, we’ll discuss the different types of football defenses and how they are run from a coaching perspective. Consider this your mega guide to football defenses!
Gaps And Alignments
Before we get started, it’s important that you learn about gaps, techniques, and alignments. Coaches will use this universal system to align their players.
The best way to understand alignments is as follows:
- Head-Up Alignments = Even Numbers
- Inside Alignments = Even Numbers With The Letter “i”
- Outside Alignments = Odd Numbers
So, for example, if the team lines up in an “Over” front, they will line up in two 5-techniques, a 3-technique, and a 1-technique. Instead of telling every player where to line up, the coach can simply say play the “Over Front.”
Each front has its strengths and weaknesses. However, the main focus for defenses to stop the run is to have a player responsible for the A Gap, B Gap, and C Gap. This will force the ball to bounce to the outside, where the defense can run it down.
Different Types Of Football Defenses
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3-4 Defense
The 3-4 defense is played by football coaches who have 3 defensive linemen who are either quick or stout and can hold gaps. The most common type of front played by the 3-4 defense is the “Tite” front.

The Tite Front is played with 4i, 0, and 4i techniques from the two defensive tackles and the nose guard.
The benefits of playing this front are it beats inside the zone by compressing the B gaps and forcing the offense to block single teams rather than double teams.
It’s susceptible to the outside and to overloaded sets if the defense wants to play any two high structures.
Next, another common front is what is known as the “Stack” front in the 3-4 defense.
The Stack Front is played with 4, 0, and 4 techniques from the two defensive tackles and nose guard.

You may be asking, does it really make a difference between a 4i and 4 technique? The answer is yes. When the offense runs gap schemes, they will block down on the 4i technique so the linebackers have to spill the football, vs a 4-technique where the defensive tackle will be responsible for spilling the football.
Last, the most common front from a 3-4 defense is the “Okie” front.

The Okie Front is run from two 5-techniques from the defensive tackles and a 0 technique from the nose guard. Coaches may substitute bigger bodies for their defensive tackles when running this front because it allows the players to speed rush off the edge.
4-3 Defense
The 4-3 defense is the most common run defense at both the youth and high school levels. The 4-3 structure of defense will have two interior defensive tackles and two defense ends for defensive linemen and 3 linebackers.
The three linebackers are often called the Sam, Mike and Will linebackers (for Strong, Middle and Weak).
The most common front in the 4-3 defense is the “Over” front. This means the defense will have two 5-techniques, a 3-technique and a 1-technique.
The 3-technique will go to the strong side, as shown as “T” in this picture below.

The 4-3 structure is a well-balanced defense that allows every player to own a gap. This means if the ball runs through their gap, they are responsible for making the tackle.
The next front is the “Under” front. This front is the same as the Over Front, except now, the 3-technique will be the opposite of the offensive strength.

Teams will use the Under Front as a way to play their linebackers to the front side. This front structure is great for teams who use their Sam as a walked-down linebacker off the edge with a tight end. It allows for defenses to be more aggressive against 21 personnel sets.
4-2-5 Defense
The 4-2-5 defense is similar to the 4-3 defense, with 4 defensive linemen. However, there are only two linebackers in the box.
The third linebacker is converted to a safety or slot corner and will travel to the offense’s passing strength.

The slot corner is often called a nickelback. This player is a key element to the 4-2-5 defense, as they need to be able to play the pass and hold the edge on the run.
Teams often put their nickelback to the field, because there is more space to cover.
The 4-2-5 defense has the same fronts as the 4-3 defense. Coaches will utilize the Over Fronts and The Under fronts, based on where the nickelback is. This helps teams keep the nickelback in or out of the fit based on his alignment and coverage.
The 4-2-5 back end often runs split field coverages. This means variations of palms coverage, cover 3, cover 4, and cover 6.
3-3 Stack
The next defense is the 3-3 stack defense. This defense is common at the high school and college levels because of its ability to confuse the offensive line.
The key component to the 3-3 stack defense is slanting and blitzing, hoping to get a sack by the offense missing a blocking assignment.
By alignment, the 3-3 stack front will align in all three Tite, Stack, and Okie Fronts.

The Sam, Mike, and Will linebackers will align directly over the top of them, hence the name 3-3 Stack.
Based on the coaches’ philosophy, the coach can slant all the defensive linemen one way and use the linebackers to fill in the open gaps. Alternatively, they can only move one defensive lineman and blitz a linebacker. There are many ways to run the 3-3 stack defense.
The hard part about running the 3-3 stack defense is dissecting where things went wrong. If the player blitzing misses his assignment, there could be a wide-open hole for the running back to run through.
5-2 Defense
Last is the 5-2 Defense. The 5-2 has 5 players on the line of scrimmage and two linebackers. The 5 players on the line of scrimmage can be all defensive linemen or 3 defensive linemen and 2 outside linebackers.
The most common type of front in the 5-2 defense is a “Bear” front. This means the nose guard plays a 0-technique, the defensive tackles play 3-techniques, and the defensive ends play 5-techniques.

The 5-2 defense is often played against teams that run 21 personnel or similar power packages and like to run the football.
Coverages out of the 5-2 defense are cover 2, cover 1, or cover 0.
What’s Next
These defenses are the most common defenses that are played in football. Coaches will create variations of these fronts to try to disguise what they are doing.
Against great quarterbacks, NFL defensive coordinators need to be creative in how they disguise fronts and coverages. This often involves slanting the front or moving players around to trick the offensive lineman and quarterback.
At the end of the day, the A, B, and C gaps need to be covered in order to stop the run effectively. That’s what each base defensive structure aims to do.
If you liked learning about football defenses, we recommend you check out our Ultimate Football Guide.
If you’re a coach and you landed here, we have an entire membership that can help you learn even more structure and coverages here.