There are two rules to defeating a double team:
1) Fight 1/2 of ONE man, not both (in other words, never take on both blockers), and
2) Keep our LB's free.
There are two keys to defeating a double team:
1) Great Pad Level, and
2) Vertical Push
First, we must have great pad level. Our DL's shoulders need to be below the OL shoulders or we will get driven off the ball every time. Secondly, we need to get our hands in the appropriate place on our visual key (near # and elbow/armpit) and not let go. We want to achieve vertical push on our key, driving him backwards and getting our heels across the line of scrimmage. If it's a scoop or combo block, the OL will be looking to leave us, so we want to hang on and turn his shoulders. When the second blocker comes in, he should not be able to get his hands on our chest because of our depth. If we feel him coming, we will turn our shoulders away from him so that he cannot get his hands to our chest. By keeping the second blocker fighting to get hands on us and maintaining a handle on our key, we will keep both defenders occupied to free up the LB's. If the OL use very tight splits or we otherwise end up in a situation where both OL have hands on our chest, we must drop immediately and hook legs to avoid giving any vertical ground and to ensure that neither blocker is able to get to our LB's.
Drill: We work the double team defeat in our 2 on 1 drill every week. In the 2 on 1 drill, 2 OL are given a call (sometimes on a card, other times verbal) and a snap count, and the DL is told where to line up (which OL to shade and where). This drill also allows us to rep other types of blocks that we will see that week.
In the first photo below, our DE on the left has gotten his heels across the LOS and turned his shoulders away from the incoming defender, not allowing the double team to get movement on him.
In the bottom photo you can see the DL has his hands on his key, #76, and is pushing vertical to not allow #60 into his chest.
