Terminology: Backside Contain

The backside of any defense is where, initially, the ball isn’t going.  Backside contain is protection for those times when an offensive play – like a reverse, or counter, or bootleg – changes direction and attacks a defense’s backside. 
  
Like containment on the playside, backside contain is about keeping the ballcarrier bottled up in the backfield and allowing the pursuit from the interior defenders to catch him before he breaks “outside” into the perimeter where the defense is weakest.
   
The assignment is performed at the edge of a formation by a Defensive End or Linebacker, depending upon the defensive scheme. 
  
Routinely the contain defender will “stay at home” or “squeeze down” and look for the ball coming back his way.   When the ball goes away, he will “trail” the play at the same depth as the ballcarrier and shut down any reverse before it gains speed. 
         
In either case, the defender is under control and will not cross the line of scrimmage and pursue the ballcarrier until he, himself, has crossed the line. 
     
Now to “squeeze down” means to replace.  The Defensive End (99) in the picture below is doing exactly that.  He’s moving into the space vacated by the Offensive Tackle who is blocking down on the weakside Linebacker (33).  From this position, he can stay “flat” – meaning parallel to the line – which keeps his outside arm free in the event of a trap block coming from the inside and allows him to read flow.

Terminology: Bootleg

A bootleg is schizophrenic or something.
                     
For starters, it’s a misdirection play.  The Quarterback fakes a hand off in one direction then rolls out to the other.
                                   
It’s also a play-action pass in that it starts out looking like a running play.  The run fake does two things: it confuses the defense and it slows down any pass rush.
                                  
And, lastly, it’s an option play — sort of.  Depending upon how the defense’s backside reacts to the Quarterback’s sudden appearance with the ball, the Quarterback has the option to either run or pass.
                             
The defense, in this case, is specifically the force defender.  He’s the lone wolf in a defense’s perimeter who’s entrusted with “forcing” a ballcarrier back into the pursuit. 
                                
When he sees the Quarterback with the ball to his side of the field, he has two choices: he can lay back and protect against the pass, in which case the Quarterback can run.  Or he can rush the Quarterback who will then throw to the open receiver.  When executed properly, a bootleg is basically a no-win situation for the defense.
                      

Now bootlegs can be run and blocked in different ways, but a typical bootleg will have the backside Guard (G) pull across the formation to block the defender at the end of the line with contain responsibility, like in the illustration below. 
                         

The contain defender has one primary job: keep the ballcarrier bottled up in the backfield.   Blocking him allows the Quarterback to get outside, into the perimeter where he can read the few defenders there and react accordingly. 
                               
Like in the photo above, a typical bootleg will also have three receivers stacked at different depths to the side of the field to which the Quarterback is rolling, giving him options at different levels.

The key to any bootleg, though, is the running play upon which it is based.  It has to be working for the defense to be fooled by the run fake, especially if the offense proposes to run a type of bootleg called a “naked”.
                      
A naked simply means that the Quarterback has no protection.  The contain defender – usually a Defensive End – is not blocked because the offense anticipates that he will overreact to flow away from him and give up contain by pursuing in the direction of the fake.
              

Once he recognizes that the play is a bootleg, it’s generally too late for him to retrace his steps and prevent the Quarterback from getting beyond the edge of the formation.
                    
Nakeds are commonly run by spread offenses that use zone blocking up front to execute their run fake.  They don’t pull the backside Guard be-cause the offense wants to maintain the illusion of a run play.
          
If the illusion works, the contain defender will be easy to spot.  He’ll be the player putting on the brakes and trying rapidly to change direction.  If it doesn’t, then Quarterback probably gets sacked.
          
Besides your basic “boot” and “naked”, there are three other kinds of bootlegs.  Each is defined by how they block the contain defender and, in the case of two, the force defender as well.  They are the Pin Play, the Pin-O Play, and the Waggle.
          
The Pin Play is run to the Tight End side of the formation.  He’s kept in to block or “pin” the contain defender inside.
           
The Pin-O does the same thing but it also brings the “offside” Guard — another term for the backside, hence the tag “O” — to block the force defender.
                     
The Waggle, however, comes to us from the Delaware Wing-T playbook.  It is run to the weakside of a formation and has both Guards pulling to block in front of the Quarterback, like in the diagram below.
                  

This explains why some Offensive Coordinators’ consider a waggle to be a bootleg that is run to the weakside — the side without a TE — while a “bootleg” is run to the strongside or towards the TE.

Terminology: “Selling the Nine”

The nine is football’s most basic and most important pass route and, yet, it’s nothing more than a race to the end zone – or at least as far as the Quarterback can throw.

                                                                                        

Selling the nine is convincing a defensive back that he’s in that race every time a receiver releases from the line of scrimmage.

                                                                 

The nine is basically a straight line.  As such, it’s the stem for many of the other routes a receiver can run.  By stem, we refer to another straight line, the one a receiver runs when he escapes the line of scrimmage and races to the breakpoint of his assigned route. 

                                                            

If a receiver can fool a defensive back into thinking he’s going deep, then the underneath routes that break off the nine open up.  Separation – the goal of any receiver – becomes easier.

                                                                 

This example of a passing tree is fairly simple, but it shows how the “9” is strictly vertical and other routes break off it. Note how even-numbered routes work inside, and odd-numbered routes work outside. 

                                                                  

Sample Passing Tree

The deception succeeds because the nine is a defensive back’s worst nightmare.   “Don’t get beat deep” is the mantra he hears in his head each time a receiver lines up.
                                                          
The way, then, a receiver deceives a defensive back is by being consistent.  Each time he runs a route that comes off the nine, he mimics the actions of a nine which derives its name from the passing trees found in offensive playbooks.  

Terminology: Big-on-Big

Also known as  BOB, Big-on-Big is a six-man – 5 OL and 1 RB – pass blocking scheme that matches offensive linemen against defensive linemen.  In other words, big guys on big guys and for the obvious reason: they’re about the same  size and strength. 

This allows the running back to block a defender more his size: a linebacker or defensive back, should they blitz.

If the defense doesn’t blitz, though, the running back is free to release into a pass route.  This assignment is called a “check release” because he checks first for a blitz before releasing. 

In the pictures below, big guys are blocking big guys and the running backs are checking for a blitz, but there is none as the linebackers are dropping into coverage.  So, once they see how the underneath coverage is developing, they’ll attack the open grass and give the Quarterback a checkdown option should everyone else be covered.

Click on each image to enlarge it.