The 3-4 defense has a lot of variations and nuances in how players are aligned. At its core, a 3-4 has three defensive linemen and four linebackers. The notable difference between a 3-4 and 4-3 is the type of defensive linemen playing them. The 4-3 typically creates one-on-ones for their players at the line of scrimmage while the 3-4 eats up blockers on the offensive line to allow their second-level players to make plays.
Why use the 3-4
While the 3-4 only has three defensive linemen, the Sam and Will linebackers are typically walked down at the line of scrimmage and play as stand-up edge rushers. The 3-4 is a little more flexible than the 4-3. The 3-4 has the ability for defenses to both two-gap or one-gap. Outside linebackers are the premier players in the 3-4 and they must be able to pass rush, hold up against the run, and occasionally drop in pass coverage. The interior three linemen skew more towards being space-eaters to keep offensive linemen from getting up to the middle linebackers.
How to Identify
The two biggest identifiers for a 3-4 are:
- Three defensive linemen with their hand on the ground
- Two stand-up outside linebackers at the line of scrimmage
Strengths of 3-4
The 3-4 has so many looks, it can be hard for the offense to deal with. Those looks can be slight changes in alignments to better demand blocks, dropping outside linebackers into coverage and only rushing three, or bringing five-man pressures by rushing both outside linebackers. The 3-4 is flexible from play-to-play and that makes it hard for offenses to gameplan against.
Weaknesses of 3-4
Need for strong interior linemen
If the interior three linemen in the 3-4 cannot demand blocks and prevent offensive linemen from climbing to the second level, the linebackers must be exceptional players. The nose in the 3-4 has to demand two blockers, otherwise linebackers will have to sift through traffic and shed the blocks of bigger offensive linemen. Those defensive linemen also must free up the outside linebackers for one-on-one pass rushing situations.
The 3-4 defense has a lot of flexibility. It can change alignments to better attack offensive formations while keeping the same personnel on the field. It needs athletic players at the outside linebacker position and guys who can eat blocks on the inside for it to be at its most effective.