The 4-3 defense features four down linemen and three linebackers. It's the most common defensive front in football, providing balance between run defense and pass rush.
Overview
The 4-3 defense is football's most traditional and widely-used front. Four defensive linemen (two ends and two tackles) control the line of scrimmage while three linebackers (Mike, Will, Sam) handle the second level.
This front provides natural gap control with each lineman responsible for a gap, and allows linebackers to flow freely to the ball. The 4-3 is effective against both the run and pass, making it the base defense for many programs.
Variations include the 4-3 Over (strength to TE side) and 4-3 Under (strength away from TE), which adjust alignments to handle different offensive sets.
History & Origin
Tom Landry developed the modern 4-3 defense as defensive coordinator for the New York Giants, creating the framework that would become football's standard front.
Key Principles
- 1Four down linemen control the LOS
- 2Three linebackers handle second level
- 3Each DL responsible for a gap (typically)
- 4Mike linebacker is the QB of the defense
- 5Will linebacker is the weakside run defender
- 6Sam linebacker sets the edge to the TE
- 7Natural gap integrity
When to Use
The 4-3 is appropriate as a base defense against most offensive sets. It's particularly effective against pro-style and 2-back offenses.
Pros & Cons
Advantages
- +Natural gap control
- +Four-man pass rush
- +Balanced against run and pass
- +Linebackers can flow freely
- +Easy to teach and install
Disadvantages
- −Can struggle against spread offenses
- −Only 3 LBs in coverage
- −May need nickel personnel vs 11 personnel
- −Can be outflanked by perimeter runs
What Coaches Call It
Different coaches use different terminology for the same concepts.
| Coach | Team | Their Term | Notes |
|---|---|---|---|
| Tom Landry | Cowboys | 4-3 Flex | Original flex variation |
| Monte Kiffin | — | 4-3 Tampa 2 | Cover 2 based system |
| Pete Carroll | Seahawks | 4-3 Under | LEO position |
Matchups
Good Against
- +Pro-style offenses
- +2-back sets
- +Power running
- +Traditional formations
Avoid Against
- −Spread offenses
- −4-wide sets
- −Tempo
- −RPOs targeting LBs
Installation
What You Need
Prerequisites for running this scheme effectively.
- ✓Penetrating 3-technique
- ✓Rangy Mike LB
- ✓Edge-setting DEs
When NOT to Use This
- !Must adjust to spread - go to nickel
- !Can be outmanned in coverage
- !Needs athletic LBs vs modern offenses