What is a crackback?

I saw where one of the Lions was charged with a crackback and could be fined by the NFL. What is it?

 

A few explanations from the web:

a

An illegal block when a wide receiver after the snap moves back to the line to block an opponent from behind or below the waist.



b

A Team A player who, at the snap of the ball,
(a) is positioned more than three yards outside the offensive tackle, or
(b) is in motion towards the ball within three yards of the offensive tackle from a point more than three yards outside the offensive tackle shall not be permitted to move laterally toward the ball and contact an opponent below the waist in the area up to five yards in advance of the line of scrimmage from sideline to sideline.



Basically if your outside the tackles by 3 yards you can't cut block a guy movign to the ball.


... i think..

 

Thanks droogie. I thought it sounded pretty serious if the NFL was going to fine him.

But I don't know if I think what you just descriped is serious enough for a personal fine toward a player. Is it?

 

i think its considered real serious because your hitting the knees and the defender isn't ready for it.

ie. corner blitz, he expects the WR to try to block him if its a run play, but not if its a pass play.

On top of that the standard block would be hands in the chest type. but the wr dives for the back of the knees and the guy in front really can't brace for it or defend it.


in a crackback block you can kinda roll up the leg and up twisting a guys leg pretty bad.