Run defense?

[Defensewins]

Originally Posted by backrow

I must have mis-heard! I'm sure I understood Mike Golic say the 2 gap was when he had to be responsible for two holes the RB could scoot through. The 1 gap was when he had one hole to cover.

Backrow, you correct.
Joe Crisp's great explaination is of gaps and placement of the DT's in those gaps. But my understanding from way wayway back from my playing days as a defensive end is exactly like yours.
My coaches taught me, in a two gap defense the defensive lineman are responsible for two gaps in the offensive line. In a one gap the D-lineman are only responsible for one gap.
It is easier to play the one gap cause you can charge your gap and not have to worry about another gap. It is easier to get sacks this way.
But the drawback to the one gap is you have only 3 to 4 D-lineman to cover six gaps. So have to depend on LB's and safety's to cover the remaining gaps if it happens to be a running play. This could distracts the LB's and Safety's from their coverage duties on pass plays if they are faked out on a play action play.