Attacking LB's?

That sounds like inexperience and lack of confidence to me. There is a moment for a linebacker that they (whether on purpose or by accident) come downhill and hit someone hard and realize they are not going to break. You hope that happens early for the kid, but it doesn't necessarily. Face it, football is unnatural. You are flinging yourself with everything you're worth at another person who is doing the same thing. Common sense says to get the hell out of the way, but you have to overcome that in your mind. I can remember the moment that it happened for me as a sophomore in high school. The kid needs to find that moment.

I would say that you "stage" a play or two for each backer in group or team time where you have a specific run play that will run right into a stunt of the backer. He won't know it's coming, but if he comes hard into his gap and "Viola" there's the ballcarrier, suddenly he has no choice but to make the play. Maybe that will spur some confidence and then aggressiveness comes with it.