The 4-3 Defense
We already looked at the 4-3 defense in our discussion of defensive linebackers and linemen. If you don’t remember, the 4-3 has four defensive linemen and three linebackers. The remaining four players are the defensive backs in the secondary—two safeties and two cornerbacks. This formation is effective against the run and the pass. On passing plays, the middle linebacker will typically cover the running back, while the linebacker on the “strong” side (i.e., the side where the tight end is lined up on offense) covers the tight end and the “weak” side linebacker also covers the running back (if he isn’t blitzing). Here is what it looks like--the defense is in blue...
The 3-4 Defense
If you understand the 4-3, the 3-4 should be easy. Instead of four linemen, you have three and a fourth linebacker joins the other three behind the linemen. The other difference from the 4-3 is that the linemen usually line up directly across from the offensive linemen, instead of in the “gaps” between them, as in the 4-3 (see below); the linebackers will typically attack the gaps instead. (Click here for a refresher on gaps.)
In a nickel formation, the defense uses five defensive “backs” (i.e., cornerbacks and safeties). In other words, there are five players in the secondary; the fifth back is referred to as the “nickelback.” The formation is called a nickel regardless of how the linemen and linebackers are situated. Therefore, there can be many variations of the nickel—the 4-2-5, the 3-3-5, etc. (the image below is a 4-2-5). This formation is useful when the offense uses a third wide receiver.
A natural progression from the nickel, the dime defense uses six defensive backs. In case you were wondering, the sixth man is called the “dimeback.” This is typically used in clear passing situations.
Stay tuned to this space tomorrow for the Prevent Defense, the Goal Line Defense, the 2-5 and the “Tampa Two.”