What is the difference between a nose guard and a nose tackle?

Answer 1

The positions are functionally interchangable in that both positions line up "nose-to-nose" with the middle offensive lineman, the Center; the difference comes in why and how the player finds himself lined up in this manner.

A normal four-man defensive line generally lines up against a normal five-man offensive line as follows ("o" = offensive linemen, including "O", the Center; "x" = defensive linemen; underscores "_" = gaps):

o_o_O_o_o

_x_x_x_x_

That is, the defensive linemen line up in the gaps between the offensive linemen.

Some run defenses call for a five-man defensive line. Adding a defensive linemen makes the number of offensive and defensive linemen the same, allowing the defensive linemen to line up directly over their offensive counterparts. The additional defensive lineman (shown as the capitalized "X" below) brought in to line up *nose*-to-nose with the Center in a five-man defensive line is properly referred to as a *NOSE GUARD*:

o_o_O_o_o

x_x_X_x_x

When a defensive formation calls for a three-man defensive line, one of the DTs leaves the field, leaving one DT and two defensive ends on the defensive line:

o_o_O_o_o

_x_x___x_

To fill the large gap, the remaining DT (see the bolded "x" below) shifts over and lines up directly over the Center to cover the territory normally covered by he and the absent DT together:

o_o_O_o_o

_x__x__x_

A defensive *tackle* who is playing in a formation that requires him to line up *nose*-to-nose with the Center is properly referred to as a *NOSE TACKLE* for plays in which he has shifted in this manner.

Answer 2

Nose tackles are defensive tackles that line up over the center. They are normally in the 3-4 or 5-3 defensive schemes.