Tialdude,
I played football for 13 years and most of it on the line and in the linebacker position. If your looking at the d line and linebacker position you will want to gain as much strength as possible (of course, info all over this website), but you will also want to gain speed for this position, in your legs and hands to shed off blockers. Ladder drills and plyometrics work great for the leg speed, and hand movements such as a speed bag or simply placing a pad on the wall and trying to keep it from falling by hitting it as fast as you can will help you in this. Good luck
