Defending the run in our 3-4 defensive scheme rests heavily on our inside linebackers ability to diagnose blocking schemes and attack the line of scrimmage with speed and efficiency. To accomplish this, our LBs need to be disciplined in their key reads, going through the same repetitive progression on every play. If our LBs can read and react quickly, not only are we gap-sound and aggressive vs. the run, but additionally we are able to run multiple fronts and coverage schemes that will give us an edge in the run game.
Our inside linebackers are primarily focused on two things: running back flow, and the blocking scheme of the offensive line. Being able to decipher the blocking scheme is very important, and we emphasize this early in our installation. Our aim is to teach the LBs how to read blocking schemes out of a 3-down front, with head-up defensive linemen. For our surface reads, we key the guard/tackle and focus primarily on the guard’s block, since he is in our LBs direct line-of-sight. The basic blocks we focus on are as follows:
Down Block:
– Down blocks nearly universally trigger our LBs to spill the play to the outside support player.
– If flow is away, the ILB is fast inside/out to the ball, and should scrape across the center.
Fan Block (G/T Double Team):
– When a guard fans out, it triggers our LB to box the play back inside to the other ILB.
– If flow is away, the ILB plays the cutback lane in the A-gap.
Zone Block:
– Split Zone: LBs fit inside the reach and adjust to the ball carrier’s path.
– Lead Zone: LBs get over the top of the reach and adjust to the ball carrier’s path.
Initially, reading these blocking schemes and reacting in accordance with our rules can be difficult out of our head-up front. However, our LBs lives get easier when we start installing off-set fronts, which predetermine the offensive blocking scheme. For example, the front pictured below is off-set to the tight end. Despite the fact that it is actually a 4-3 under scheme with 3-4 personnel, the reads for the inside linebackers are no different. The ILB to the tight end has a 1-technique, and knows that he can expect a down block by the guard on an iso play. Thus, he is educated to know that he is a spill player if iso comes his way, and a scrape player if the flow is away from him. Conversely, the LB to the 3-technique side (away from the tight end), knows to expect a fan block from the guard, and will thus box the iso or play the cutback if flow is away from him.
The next diagram shows how we would defend the zone play out of the same front. It should be noted how similar the fits are to how we would attack an iso play. The illustration of the runner cutting back across the center shows a vice between our two inside linebackers in the gap, much like we would fit fan block iso to the 3-tech. Additionally, the illustration of the play hitting to the 1-tech shows the ILB fitting inside and essentially spilling the play to the outside support, as he would vs. iso his way. We find it very beneficial to point out the uniformity in how we fit different plays and explain these similarities to our players, as it gives them a greater understanding of how the defense operates as a whole.
Pull Reads
The next important step is making sure that our LBs understand the importance of identifying pulling linemen. Simply put, we instruct our LBs that pulling linemen add extra gaps to the other side of the formation, and that we as LBs are responsible for defending those gaps. So, if a lineman pulls in a power or counter play, it is our job to communicate the pull and account for the additional gap on the other side of the center. We teach our LBs to scrape at depth and track the path of the puller to the open gap. This is the key component in defending the power play, as pictured below. Note that the ILB is in the direction that the play doesn’t need to play it any differently. He just follows what his rules tell him. Thus, the ILB to the 1-tech spills the puller because of the down block, and the ILB tracking the puller simply overlaps him and fits the gap.
We can relate to the way we respond to pullers to the way we defend lead zone as well. The combination of a reach block and full flow by the running backs triggers our LBs to get over the top of the reach, rather than fit inside as they would vs. split zone. This ties into how we play the pull, since when coupled with full flow RBs, we treat pulling linemen and reach blocks in a similar fashion; that is, we must work over the top and avoid being cut off from the ball. Thus, our fits vs. lead zone are similar to how we fit power, since the ILB away from the RB flow has a pivotal role in defending the play (see diagram below).
Teaching the ILBs how to respond to these different types of blocks allows us to adopt a universal approach in how we defend the run, regardless of the scheme. We don’t need to over-coach how to defend specific plays, like one-back power and different variations of counter, or even read option plays. Our ILBs know how to react when a lineman pulls, how to fit zone blocks, and whether to spill/box the play based on scheme (which is often predetermined by the defensive front). Even when we defend the read option with concepts like gap-exchanging with D-Linemen, these adjustments come as natural change-ups to the way we fit the base version of whatever play the offense is running.
Once our LBs have a mastery of these reads and how to properly fit different run plays, we can really open up the arsenal defensively. One of the biggest benefits to teaching out of 3-down fronts to start is that it as our installation progresses, we gain the capability to run 4-down schemes (as with our off-set fronts) with 3-4 personnel still on the field. When our players have a good grasp of the defense, we can alternate freely between 3-down and 4-down defensive schemes without skipping a beat or changing personnel. This makes our array of defensive fronts and coverage variations virtually limitless, giving us the ability to shut down the run by applying the desired front/coverage and allowing our LBs to play fast and physical.