There are three common stances used in every football game: the 2-,3-, and 4-point stances. Of these, the 3- and 4-point stances involve getting down low to the ground to create leverage.
The 3-point stance is the most common stance used by offensive linemen. Fullbacks also usually line up in a 3-point stance.
A 4-point stance is sometimes used by defensive linemen, as well as interior offensive linemen in short-yardage situations.
There was some talk about banning downstances because of the head-to-head contact they often create at the line of scrimmage. However, these complaints were very small and have gained little traction because these stances are so integral to the basic parts of the game.