3–4 base defense
The 3–4 defense which evolved from the old 5-2 defense has gained popularity since the seventies due to the present day spread formations and the passing game which renewed its use by modern professional and college football teams. The 3–4 defense is so named because it involves 3 down linemen and 4 linebackers. There are usually 4 defensive backs. One basic approach using the 3-4 scheme is the ability to get lined up versus spread offensive formations and the ability to drop eight defenders into coverage while only rushing three defenders. When only rushing three defenders you are primarily wanting to contain the quarterback allowing eight cover defenders to occupy all throwing lanes.
Typically, there are two major variations of the 3–4 defense. Both variations are directly related to coverage schemes on obvious passing downs. For the first type, the outside linebackers (inverts or over hang players) will rush the quarterback, the great majority of the time. On key situations, the rush linebacker will be sent to cover the flat on the opposite side of the blitzing defensive back; this is known as a “zone blitz”. This scheme requires outside linebackers to have the ability to back pedal and drop into coverage, of course they do rush the passer at times, it is just that they are much more likely to drop into coverage.
The 3–4 defense was originally devised by Bud Wilkinson at the University of Oklahoma in the 1940s. Chuck Fairbanks learned the defense from Wilkinson and is credited with importing it to the NFL.
The nose tackle and the inside linebackers, those are three guys that are very important. But when you go through it, the nose tackle is probably the single-most important guy. In the 3-4 scheme you want your nose guard to draw double and triple team blocks to free your inside linebackers up and it is to be noted that the nose doesn’t necessarily have to be large as speed can accomplish drawing both guards to help the center block the nose.
The defensive line is made up of a nose tackle (NT) and two defensive ends (DEs). Linemen in 3–4 schemes tend to be larger than their 4–3 counterparts to take up more space and guard more territory along the defensive front. 3–4 defensive ends were usually defensive tackles (DTs) when entering at first and this was due in part to the old 5-2 philosophy. They must be strong at the point of attack and are aligned in most cases head-up on an offensive tackle. First and foremost, they must control run gaps. Size and strength become more of a factor for linemen in 3–4 defenses than in 4-man fronts because they move primarily within the confines of line play and seldom are in space using athletic ability. Ideally 3–4 DEs should be able to beat double teams by getting a push. The 3–4 nose tackle is considered the most physically demanding position in football. His primary responsibility is to control the “A” gaps, the two openings between the center and guards, and not get pushed back into his linebackers. If a running play comes through one of those gaps, he must make the tackle or control what is called the “jump-through”—the guard or center who is trying to get out to the linebackers. Since most college teams run a 4–3 defense, most college DTs are more of a 4–3 tackle than a true nose tackle, which makes good 3–4 NTs hard to find.
The base position of NT is across from the opposing team’s center. This location is usually referred to as zero technique. The two DEs flank the NT and line up off the offensive guards. The location off the offensive guard is usually referred to as three technique.
Some 3–4 teams use the three down linemen primarily to occupy the offensive linemen. In such systems the defensive linemen are assigned two gaps to defend. The NT is responsible for defending plays which occur in the spaces, or gaps, between the center and guards. Each of those spaces is called an A gap. Flanking the NT, DEs defend the gaps on either side of the tackle he lines up across from. Each guard-tackle gap is a B gap and the space outside each tackle is called a C gap. Other 3–4 teams (such as the San Diego Chargers and the Dallas Cowboys) primarily
make each lineman responsible for only one gap.
In a 3–4 defense, four linebackers which make up two inside linebackers (Mike and Will) and two over hang players (Sam and Rover) are positioned behind the defensive line. The linebacker unit is made up of two inside linebackers (ILBs) flanked by two outside linebackers which in some circles are called outside inverts or over hang players (OLBs). The OLBs or Sam and Rover as they are called in this manual often line up closer to the line of scrimmage than the ILBs, but may also be positioned at the same depth or deeper in coverage than the ILBs (though this is somewhat rare).
Strengths of the 3–4 include speedy ILBs and OLBs in pursuit of backs in run defense and flexibility to use multiple rushers to confuse the quarterback during passing plays without being forced into man-to-man defense on receivers. Most teams try to disrupt the offense’s passing attack by rushing four defenders. In a standard 4–man front alignment, these four rushers are usually the four down linemen. But in a 3–4, the fourth rusher is usually a linebacker, though many teams, use a talented safety to blitz and confuse the coverage, giving them more defensive
options in the same 3–4 look. However, since there are four linebackers and four defensive backs, the fourth potential rusher can come from any of eight defensive positions. This is designed to confuse the quarterback’s presnap defensive read.
A drawback of the 3–4 is that without a fourth lineman to take on the offensive blockers and close the running lanes, both the defensive linemen and the linebackers can be overwhelmed by blocking schemes in the running game. To be effective, 3–4 linebackers need their defensive line to routinely tie up a minimum of four (preferably all five) offensive linemen, freeing them to make tackles. The 3–4 linebackers must be very athletic and strong enough to shed blocks by fullbacks, tight ends, and offensive linemen to get to the running back. In most cases, 3–4 OLBs lead their teams in quarterback sacks.
Cornerbacks play similar roles in the 3–4 and 4–3 base defensive schemes.
Depending on the scheme, safeties may play mainly pass coverage or support the run heavily. The 3–4 defense generally uses four defensive backs. Two of these are safeties (Bandit the Strong Safety and a Free Safety) , and two of them are cornerbacks. A cornerback’s responsibilities vary depending on the type of coverage called. Coverage is simply how the defense will be protecting against the pass. The corners will generally line up 3 to 5 yards off the line of scrimmage, generally trying to “Jam” or interrupt the receivers route within the first 5 yards. A corner will be given one of two ways to defend the pass (with variations that result in more or less the same responsibilities): zone and man-to-man. In zone coverage, the cornerback is responsible for an area on the field. In this case, the corner must always stay downfield of whomever it is covering while still remaining in its zone. Zone is a more relaxed defensive scheme meant to provide more awareness across the defensive secondary while sacrificing tight coverage. As such, the corner in this case would be responsible for making sure nobody gets outside of him, always, or downfield of him, in cases where there is no deep safety help. In man coverage, however, the cornerback is solely responsible for the man across from him, usually the offensive player split farthest out.
The free safety is responsible for reading the offensive plays and covering deep passes. Depending on the defensive call, he may also provide run support. He is positioned 10 to 15 yards behind the line of scrimmage, toward the center of the field. He provides the last line of defense against running backs and receivers who get past the linebackers and cornerbacks. He must be a quick and smart player, capable of making tackles efficiently as well as reading the play and alerting his team of game situations.
The strong safety (Bandit) is usually larger than the free safety and is positioned relatively close to the line of scrimmage. He is often an integral part of the run defense, but is also responsible for defending against a pass; especially against passes to the tight-ends.
“The 3-4 gives you the ability to adjust, to stay balanced and to adapt.”
Perhaps the most important cog in a 3-4 defense is the nose guard. He needs to be big enough and strong enough to take on double-team blocks, and he can’t allow guards to reach the linebackers behind him.
A defensive end’s role also changes significantly in a 3-4. In a 4-3 alignment, defensive ends line up outside a tight end or offensive tackle, where they hope to use their speed and athleticism to beat blocks. Most of the time, an end’s sole responsibility is to rush the quarterback and collapse his pocket. In a 3-4, an end’s most important job is to control gaps and beat double-team blocks to push the pocket.
Because their sole responsibility often is to take on blocks, playing nose guard and defensive end in a 3-4 is considered somewhat unglamorous. More than anything else, their job is to free up linebackers to make plays.
The weak side linebacker (Rover) usually is the premier pass-rusher in a 3-4. But he also has to be big enough and strong enough to beat blocks from offensive tackles and running backs. A strong side linebacker (Sam) often is asked to drop into space and cover tight ends and running backs on passing plays. The two inside linebackers (Mike and Will) are supposed to find holes in the line and make plays in the running game or pressure the quarterback.
One of the biggest advantage of a 3-4 scheme is its unpredictability because, any of the four linebackers can blitz on a given play, or one of the outside linebackers can move to the line of scrimmage as a stand-up end.
“If you’re multiple in what you’re doing, you can bring any of the four linebackers at any time, make your opponent. have to figure out which guy is going to be coming.” That unpredictability also tends to lead to more turnovers. I think the 3-4 structure can present issues on where the pressure is coming from, particularly against the spread offenses. You can drop bait; you can bring guys from different sides. So really the offense cannot predict where the pressure is coming from.”
Finding the right players to fill roles in a 3-4 often is easier than finding 330-pound tackles, which are necessities in a 4-3. The availability of capable linebackers in recruiting is one of the reasons so many teams are moving to a 3-4.
About the Author of this post:
Jerry Campbell has over 30 years of high school and college coaching experience. He has experience as a head coach, offensive coordinator, and various position coaches. He has written numerous football coaching articles in various publications, is the author of over 30 books on coaching football, and has produced 12 coaching video series. Additionally, he is a nationally sought after speaker on the coaching clinic circuit.