Concept Wednesday – Duo

For Concept Wednesday this week, we get our second guest post on Husker Chalk Talk.  This is one is brought to you by an offensive line coach/offensive coordinator extraordinaire from the great state of Kansas.  He’ll be talking Duo, the Huskers’ go to running concept when they need to pick up yards in the fourth quarter.  It may be the single best post we’ve had up on Husker Chalk Talk and it’s got lots of stuff for you to digest, so I’ll let him take it away.


Nebraska’s offense under Danny Langsdorf utilizes a variety of zone runs, but one of the staples of the run game is actually a gap based play, Duo.  Duo is simply get as many double teams at the point of attack as possible, get 4 legs on 2 legs, create vertical movement, and displace defenders.  In my opinion, this is one of Nebraska’s “identity” run plays, and you could really see this in the Rutgers game.  Some variation of Duo was run 31 times versus Rutgers according to one of the Husker offensive linemen.  Nebraska ran the ball 47 times in that game, Duo and its variations accounted for roughly 66% of their run game.  Langsdorf obviously found something he liked in how Rutgers aligned, and how to attack it.

Many people will confuse Duo and Inside Zone.  They look very similar, the backfield action is very similar, but beyond that, the reads and the nature of the double teams are different compared to inside zone.  That is the nature though of a gap scheme vs a zone scheme.  The key differences between the two are in Duo, the double teams are working away from the point of attack, while in zone, the double teams work towards the point of attack.  The RB’s read is also different, as the RB will read the Mike linebacker to initiate his path, while in inside zone, the RB will read the block on the first down lineman to the point of attack.  Let’s take a look at Duo.

The big benefit of hitting Duo consistently, besides penetrating the defense, is the play-action threat.  If the D starts to get the 9th guy in the box, i.e. the other safety, a post by the #1 receiver will be there, plus you can work a deep cross by the WR responsible for the 8th defender.  This allows the offense to hit some nice deep shots vs teams trying to play heavy in the box.

Blocking Rules

As far as rules go for Duo vs Rutgers 3-4 Defense:

Backside OL

  • Backside guard (BSG) & Backside tackle (BST) will work a wall technique and look to block the 2 most dangerous defenders to their outside.

Frontside OL, TE & WR

  • The playside guard (PSG) & center (C) will double the 1st down lineman (DLM) on the center on out to the backside linebacker (BSLB), the Will.
  • The playside tackle (PST) & TE will double the next DLM on out to the Mike.
  • The 7th blocker will work a path in to out and block out the force defender, opening up the alley.
  • The 8th blocker, typically a WR, will work to block the 8th defender if he’s in the box, or crack him from his position.  Usually, that WR will align tight or motion to a tighter alignment to position himself to block that 8th defender the OL can’t account for.

RB rule/read for Duo

  • RB should run a tight path to the PSG’s butt and read the Mike linebacker.  If the Mike plays downhill and plugs, he should bounce into the alley.  If the Mike linebacker scrapes over the top into the alley, the RB should dive underneath the outside double team and hit vertical.

Play #1

Duo #1  comes in the 1st quarter at midfield on 1st and 10.  The offense starts with a shift, trading into a tight Bunch Left look.

Duo 1.png

In this Duo example, what you are looking for is the Center working with his PSG, back to the BSLB, the W.  That’s your first double team.  The second double team is going to be from the PST and the wing.  They are going to double the 5 technique to the Mike.  The TE in the Nasty (or reduced) Split is going to work to kick the D gap  defender, and the WR is looking for the 8th defender in the box, up to the safety.  On the backside, the BSG is looking to wall out the 3 tech and the RT the same on the backer. 

The TB’s read is the Mike, he will cut off what he does.  If the Mike plays downhill and looks to fill the B gap quickly, the PST will come off and pin him inside, while the back bounces outside.  If the Mike scrapes over the top, the double team should stay on, and the back will cut up inside the double team.  Pretty simple, make the Mike wrong, get 4 legs on 2 legs, and get vertical:

Duo 1.gif

This first Duo turns out for a nice gain.  Foster and Decker work together, Foster quickly turns his man inside, and Decker climbs, sealing the W away from the play.  The other frontside double, which barely occurs, gets the job done.  The TE gets nice movement eventually on the 5, and Gates climbs to the Mike.  The Mike plugs, Gates eats him up, and the edge blockers did their job.  It’s now 1 on 1 with a corner.

My only critique would be for the front side double by Gates & Ketter to actually be a double and get more movement.  If the M scrapes, you don’t even have to block him, the back will make him wrong.

Play #2

Duo #2 is in the 2nd Quarter, 1st & 10 from our 13 yard line.  It’s the same shift to formation, same play, defensive look is slightly different with an 8th defender in the box.

Duo 2.png

Same basic assignments as the first example.  This time, the wing and the RT stay on their double much longer, the Mike plugs and is picked up.  8th defender in the box is picked up.  The RB IMO makes the wrong read/cuts the wrong way.  He does see an open window backside, but that’s not the play design, and he ran it more like an inside zone (IZ) cutback.  The CB is in the hole to where he should have cut to.  It’s a CB against Ozigbo.  Good match-up.  If the 2nd double by Decker and Foster was vertical, that cutback is there.  Overall, an okay job by the OL on Duo.  It would be nice to stick on those doubles longer, and not come off to their LBs too soon:

Duo 2.gif

Play #3

Duo #3 rolls out on 2nd & 5 in the 2nd Quarter.  Here is a variation of Duo, using the RSS favorite guy, the fullback.  Same basic play concept, 2 double teams at the point of attack (POA), kick the force, TB reading the Mike.  You’ll see the TE & LT double to the Mike, LG & C double to the W.  Backside will wall out.  FB kick the D gap defender, WR on the top side will fit on the 8th defender.

Duo 3.png

What actually happens in this play did not go to plan.  The defense called an effective line stunt to mess with the two double teams.  The PS 4i slants to Foster and the 0 loops off his butt to the PS.  That’s tough, I don’t care what OL is blocking it.  The 1st double team doesn’t pick up the 4i, leaving the Mike unblocked, the 2nd double team didn’t prevent the 0 from looping, leaving him unblocked.  But the back did a nice job making a man miss in the hole and getting positive yardage:

Duo 3.gif

Play #4

Duo #4 – Same variation from above, similar result.  A couple of things doomed this play from the start.  But it had to potential to hit big for a TD.

Duo 4.png

1st off, the 4i reduces to a 3 tech on Foster’s side, so it’s not an easy wall for him.  And the 0 tech shifts to a 1.  Decker and Farmer should double the 1 tech to the W, but Decker comes off right away.  It would be nice for them to stay on and work the 1 tech to the W and create that vertical displacement.  That doesn’t happen here.  The double between Jaimes and Ketter, frankly, isn’t very good.  Ketter’s hat placement is off which really inhibits what the RB can do on his read. The Mike comes downhill quickly and Jaimes has to come off, with little power under him, and the Mike is able to impact the play.  One other big problem on this is the RB’s read.  The Mike plugs, he needs to make him wrong and bounce outside between Ketter and McNitt’s block.  McNitt and Lindsey do a very good job, with McNitt opening up the alley, and Lindsey getting a nice hat on the 8th defender. 

Overall, if Ketter’s hat placement would have been on top of the 7 tech, and the RB bounces outside like he should when the M is downhill…this is potentially a walk-in touchdown:

Duo 4.gif

Play #5

Duo #5 – 4th Quarter, 1st & 10 on the 22 yard line.  Different formation, but same play.  Take care of the safety with a motion WR

IMO, this is the best of the bunch as it shows what the two double teams do at the POA and what this play is supposed to look like.  Here are the assignments:

  • Wing TE – Block out
  • PST & PSTE – Double to Mike
  • PSG & C – Double to Will
  • BSG, BST, & BSTE – Wall out
  • TB – Read Mike

Duo 5.png

Before even watching the clip, this is a pretty good still frame below of just what Duo is trying to accomplish…vertical displacement, penetrate the defense.

Duo 6.png

On the film, you’ve got 4 legs on 2 legs, creating movement, the TE is kicking out the OLB.  The WR is looking for the 8th guy fitting into the run game.  Just from this still frame, I can tell you, it’s going to be a good gain.  Notice how the 2 double teams are puncturing the defense, driving them off the ball.  Yes, the vertical leverage could be better, but there is movement being created.  The RB is hitting and reading this one nicely.  

If Gates gets to what his aim point should be, inside leverage of the double, the RB gets through the line, untouched into the secondary.  Nonetheless, it’s still a solid job by him and a nice play of Nebraska establishing an identity play and wearing a team out with it:

Duo 5.gif

Wrapping It Up

A recap for you TL;DR guys.

  • Duo is a physical, gap scheme that can look like inside zone
  • Usually, it features 2 POA double teams focusing on vertical displacement of the DLM
  • The RB reads the Mike LB and cuts off of him
  • Looks to be one of Nebraska’s “identity runs” they are trying to establish
  • Up front, Nebraska ran this scheme for the most part, okay.
  • Consistency isn’t quite there yet, but it’s not as far off as some would think.

Hope you enjoyed the commentary.  GBR

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