The 3-4 defensive mission statement:

The 3-4 defense is all about confusion.  Using strong linemen to occupy the offensive line at the point of attack, athletic linebackers are able to attack from various angles to pressure the quarterback or stuff the run.
The 4-3 usually relies on the down linemen to penetrate.  This penetration by the linemen disrupt running plays & put pressure on the quarterback as well.  The defenders will line up in gaps and attack those holes when the play starts.  In the 4-3, the men in front of you are simply obstacles to get around if you’re a linemen.  You want to ‘defend the run on the way to the quarterback’ in most 4-3 defensive schemes.  The scheme, as far as the down linemen are concerned, is about speed, agility, and athleticism.

However, the 3-4 is based on strength, grit and leverage if you’re a defensive linemen.  Instead of lining up in a gap between two linemen (often referred to as a ‘one gap’ defender), all 3 linemen play what is called a ‘two gap’ style of defense.  Instead of lining up in or near a gap, being responsible for anything that comes through that hole, a two gapper lines up directly in front of the lineman he is to attack,and is responsible for controlling both the gap to the left and the right of the man on offense.  This is obviously much more physically demanding, and requires players who are much larger and stronger than their 4-3 counterparts.  A lot of the time, 4-3 defensive tackles end up playing 3-4 defensive end.   As you can see, the responsibilities for each lineman essentially double in the 3-4:

Occupying multiple offensive linemen like this open up all sorts of opportunities for the linebackers and the defense. To make the 3-4 engine ‘go’, the nose tackle (the middle defensive lineman) must command a double team.  This will open up a gap for blitzers to come through.  If the nose tackle doesn’t command a double team, a lot of what follows is moot.  Below is an example of an offensive blocking scheme against a 3-4 line:

As you can see, the offensive guard and center both attack the nose tackle, and the offensive tackles both engage the defensive ends.  There is on ‘free’ blocker for the offense, who kind of chips off of the end.

Traditionally, teams will rush the 3 linemen and bring one or maybe two linebackers on a blitz, while playing zone coverage behind the blitz.  In other words, the players that do not rush the passer will stay back and guard and area of the field, anticipating a quick throw from the quarterback under duress from the unblocked rusher.  Let’s presume the offense is running a pass play, uses the above blocking scheme, and the defense called a simple ‘overload blitz’ coming off of the edge.  That would look something like this:

As you can see, the blitzers overwhelm one side of the field, with the players behind the play dropping back and waiting for the quarterback to throw (if he has time).  Because the nose guard has occupied two blockers, holes develop that allow linebackers to slip through, causing all sorts of chaos before the offense can really even get the play started.  However, a lot of the time offenses can do an OK job of defending against just one or two free blitzers.  That’s where something even more disruptive comes into play.  Zone blitzes can be run out of a 4-3 or a 3-4, but it’s especially effective when you have one extra linebacker to work with.  Zone blitzes usually take at least one person that you expect to rush, drop them back into pass coverage, while overloading one side of the field with rushers.

Let’s assume again that we’re working from this basic blocking scheme:

Instead of all 3 linemen rushing, the end on our left will drop back into coverage, and the 3 linebackers from that side of the field will blitz.  2 of them will rush immediately, while one will delay, waiting for the offensive linemen to react to the first wave, and then running around those blockers.

These sorts of plays are textbook 3-4, and what make the entire scheme so disruptive.  The problem of course is getting the right players.  You need big, strong defensive linemen.  You can’t take a play off, you have to come to fight every play, and you have to work to occupy multiple linemen on every play.  You also need linebackers who are fast, strong, and smart.  The middle two linebackers especially must be larger than normal linebackers, as they are taking on offensive linemen more often than their counterparts in a 4-3 (4-3 linebackers usually are in pass coverage, or guarding tight ends or running backs, but rarely engaging linemen directly).

If, and that’s a big if in the college game, you’re able to get the right players in place, you can really cause problems for opposing teams.  It’s very similar to Paul Johnson’s offense in that teams just can’t effectively prepare for what they’re going to see in such short time, and it usually will lead to breakdowns.  These breakdowns should become turnovers, and help Tech win a lot of games with an already potent offense.

I’ll go into more detail about GT’s exact implementation, the types of players needed and if Tech actually has them before the first game next Saturday.

By all means, let me know if anything didnt’ make any sense or you’d like me to go into further detail.

So one of my friends asked me in reference to my prior post what I meant by ‘vectoring’ .  This is a defensive philosophy popularized by Jim Bates, who had some success in Denver and Miami with the scheme, but ultimately was run out of town.

The vectoring or Run Control style of defense exists to help the entire team work towards forcing an opposing player into a zone of the field that the defense wants them to be in.  It’s kind of this odd mixture between man coverage and zone coverage, and uses outside linebackers to move players to the middle of the field while NOT making actually making the tackle.  That’s what the MLB is for.

Again, the OLBs do not typically make tackles.  Odd, but it makes sense if you think about it.  Instead of working in a zone or a man situation where one player takes a risk that can or may not success (read: attempting to make a solo tackle), the Run Control/ vectoring system basically uses OLB players as traffic cops to force a player back into the center of the field.  Basically, this increases the likelihood there will be multiple players available to attempt a tackle, and thus reduces the likelihood of missed or broken tackles.

There are some very important things you need to make this system work, however.  

You need big, strong interior linemen to occupy the offensive line.  These players rarely will get sacks, as their job is to simply hold the blockers in place from the other team, so that the linebackers are then free to funnel the play to the middle linebacker (and the rest of the team).   The defensive ends will get multiple sack opportunities coming off of the edge, mainly as a result of the interior linemen creating mismatches (double teams) on the inside.  These players must also be able to peel off on running plays and meet the runner.

In essence, you use your big strong linemen to stop runs up the middle, forcing the team to try to work their way outside of the tackle box.  As soon as they try this, your outside linebackers and corners must funnel the runner back towards the middle, where the rest of the team is waiting.  Eventually, you shut the run down completely.  At this point, your speedy defensive ends tee off on the QB because of the tight man-to-man coverage your corners put on the receivers.

Sounds logical in a way, but it requires you to have a lot of players that are hard to find.  You need two big 2 gap defensive tackles.  Good luck tracking two of those down and being able to afford them.   You need two lock-down corners that can play man-to-man for most of the game.  Again, expensive positions and hard to find the talent.  You need fast, intelligent OLBs who understand the play happening behind them and funnel the opponent accordingly. And finally, you need a tackling machine at MLB.  Everywhere Bates has gone, the MLB in his defense is a top 5 tackler that year.

So when you consider the needs of this defense and you think of the personnel that were in Tampa when he showed up, it’s kind of a head scratcher.  TB had:

•  Smaller, 1 gap penetrating offensive linemen (1 gap = you are responsible for the gap between two opposing linemen and you tackle whatever comes through it.  2 gap = you are responsible for controlling a lineman in front of you and whatever happens to the gaps to his right or left.)
• Smaller, faster corners who work well in zone coverage.

TB got run all over.  It was no contest.  They gave up 158.2 yards per game, dead last in the league.  The smaller defensive tackles couldn’t do their job, which made the entire system break down.  Now we’re back to a variant of the Tampa 2 for the Bucs, that take advantage of the smaller size and relative quickness of it’s players.  Over the last half of the season we saw a huge improvement as the team went back to attacking instead of reacting.

So in conclusion:

System Advantages:

• Speed on the outside (DE and OLB) allows for effective blitzing in the pass game.- Takes away the outside run & forces teams to throw the ball into tight man coverage.
• Meets the inside run with DTs and a MLB dedicated to run stopping assignments on most every play.
• Swarm type defense creates multiple fumble recovery possibilities.

Disadvantages:

• If the runner beats the defender to the sideline and turns upfield, it’s a bad, bad day.  The rest of the team is waiting in the middle of the field.
• Requires the DTs to be above average 2 gappers, big, and patient.  Also, they cannot be relied upon to rush the passer.
• Steep learning curve for the players.
• In general, requires a perfect set of player types for the system to run well.