[Bull got out!]

Probably the most common defensive formation you see at the high school level. Many will call it a 3-4, but it's a 5-3 with the secondary usually playing cover 3.

The difference between a 5-3 and a 3-4 is personnel.  

a 5-3 is made up of a true Noseguard, two true DT’s and two True DE’s.  They are bigger but quick linemen that can hold up and shed the offense.  

the linebackers are made up of run stoppers which are strong and mainly thicker linebackers that can play in the trenches.  You have a Mike (middle), Will (weak side), Sam (strong side) 

the Sam is athletic and doesn’t mind to stick his nose in the action. 

as for the 3-4 you are using more athletic players except for the Nose he’s a hole plugger.  You have a Nose, and two DE’s.  And your linebackers are spread out and they are more of zone and situational rather than gap responsible.  

if you are playing a team that likes to run Jet, screens and outside you would play the 3-4, of you are playing a team that likes to ground and pound, you might want to run the 5-3. 

these defenses are quick to adapt during a game but you need to have the right personnel to do so.

I totally agree!!!!!! Nice evaluation!!!