Welcome back to "Chalk Talk" with LB Coach. In Part I he gave Notre Dame fans a little insight into what we can expect heading into the 2010 season. In this installment he gives us a little more insight into the basics then delves into the specific responsibilities of the defensive line. Enjoy. Whiskey
When a defense is a base 4-3 it means that there are 2 down linemen on each side of the center. Those down linemen are typically aligned on the inside or outside shoulder of the offensive guards, tackles or the tight end. You will hardly ever see a defender aligned directly over the offensive lineman. He will be shaded one side or the other based on the huddle call, field strength or formation strength.
The two defensive tackles will gap control either their A gap or their B gap depending on alignment. The Mike or middle linebacker will fill the opposite gap against the run. This is all basic football stuff and obvious to even the casual fan. The 4-3 front is called an "even" front because it's balanced with two defensive linemen on each side of the center.
Because there are 11 positions, the offense is not balanced so it is easier to outnumber a balanced defense with strength of formation. To cover the offensive strong side the extra defender must either come from the secondary or the linebackers must shift over to compensate. The 3-4 defense is an "odd" front defense and with a nose tackle aligned on the head of the center, it is easier to get an extra man to the strong side of the offensive formation or to the side that the ball moves to after the snap.
The Defensive Line
The nose tackle is the big difference in the two defenses and once you have a great nose tackle you can force an offense out of what they want to do by occupying the center and many times a guard as well. With 3 down linemen and 2 outside linebackers, either outside linebacker can walk up and become an extra front guy to the side of the offensive strength or tendency. This flexibility makes it easier to put more people on the side of the formation that you want as it allows either outside linebacker to become an extra down lineman. With the nose tackle pursuing inside out once a play starts to that side you now have 3 defenders on the line of scrimmage to play the run instead of the 2 you have in an even front. That extra guy can make a world of difference in successfully stopping a running team.
Notre Dame's task this spring and pre-fall is to find that nose tackle that can destroy the center's block and force double teams so the linebackers can move in and out without the threat of an uncovered offensive lineman blocking them. The hardest position to teach a defender is a head up or 2-gap alignment. He must possess cat quickness, superior strength and react to the center's block so he cannot be cut off ball side. The best way for an offense to cut the nose tackle off is a down block by the guard but when that happens the inside linebacker must quickly fill that hole and replace the nose tackle in that A gap.
Just the teaching time alone it takes to find and instruct the techniques of a great nose tackle makes the transition from a 4-3 to a 3-4 defense very difficult indeed. It's like a right handed batter trying to learn to bat left handed. Fortunately, the Irish have several outstanding prospects for nose tackle so I believe they will find the right guys for the job. Coaching becomes paramount as all of these new techniques must be learned and perfected with repetition. It has to become second nature when the center's head moves right or left as to how the nose tackle will react.
The defensive ends, or tackles as I learned to call them playing with 5 down lineman back in the 60's and 70's, also have a different role than they do in an even front. Most defenses align their tackles a shade outside the offensive tackles but some will play 2-gap as well depending on their physicality.
The tackle to the tight end side must be ready to play the double team block and the backside tackle must squeeze down the line without penetrating the line of scrimmage to play the cutback run. It is not unusual to have a strong tackle and a weak tackle with different body types to take advantage of their responsibilities. Against spread teams with no tight end you like the backside tackle to be your contain rusher and the strong tackle to be your free lance guy since he usually has an outside linebacker rushing from his outside.
Many college coaches don't want the headaches involved with teaching the odd front and many of today's players don't want to be coached that hard. The 3-4 philosophy must be sold to the players and the players must buy in or the transition will not work.