46 for 3rd-4th grade

I think a 4-4 or 4-6 would open you up more to the inside then a 6-2. I percieve them as better pass defenses. And at the 3/4 grade level about 90% of the plays are running. Also the 4-4 or 4-6 at this level would be a treat to a coach with a sizable backfield he would just bang up the middle at 3-5 yards at a shot eating up the clock.

Our defense also ran the 6-2 as well as a 5-3 at the 3rd/4th grade level. They both faired well against the weaker less disciplined teams. However, against teams that had a more disciplined line who followed their assignments like gospel, both these defenses had some issues as you would expect...Also, these are the two most commonly used defenses at the peewee level (at least where I coach) so the opposing coach has prepped for them. After sqeaking into the playoffs this past year, our first game was against a team that had astronomically crushed us the week before (the actual score is too embarrassing to post).
In the week before the game we completely revamped the defense. We went with a modified 5-3.

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In this formation the MLB always goes. Either in a blitz package or from the line of scrimage as a lineman. As you can see below, when ever the MLB comes into his assigned gap the tackle adjusts to the opposite gap. This exploits age level blocking assignments allowing faster penetration into the backfield.

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At the 3rd and 4th grade level in our league we rarely see passing, how to beat the sweeps and off tackle is the key and if we do see passing the qb will normally scramble if he reads the LOS collapsing. This is an extremely aggressive defense and gambles on the fact that you have the horses to get through the LOS quickly. The nice thing is that if you call wrong you still have the same coverage as you would in a 5-2 on the opposite side. This D has more calls...but just three were needed to hold a well disciplined team that disgraced us a week before to 0-0 for 4 quarters (only to lose in over time). This is because it attacks the blocking assignments and allows adjustment for field position tendancies. Its designed to force the Offense to start reacting to where they believe the defense id going to strike. On a side note...at these ages...if you can put 2 players in there back field every play...The quarter back usually starts to get panicky and starts making mistakes. With this defense though you must have a real bull to play the MLB and two smart ILBs. If your looking for something different. This may be something to try. What I like is its versatility and for the age level its easy to learn quickly.