a. Lineman.
1. A lineman is any Team A player legally on their scrimmage line (Rule 2-21-2).
2. A Team A player is legally on the scrimmage line when facing their opponent’s goal line with the line of their shoulders approximately parallel thereto and either (a) they are the snapper (Rule 2-27-8) or (b) their head breaks the plane of the line drawn through the waistline of the snapper.
b. Interior Lineman.
An interior lineman is a lineman who is not on the end of their scrimmage line.
c. Restricted Lineman.
A restricted lineman is any interior lineman, or any lineman wearing a number 50-79, whose hand(s) are below the knees.
d. Back.
1. A back is any Team A player who is not a lineman and whose head or shoulder does not break the plane of the line drawn through the waistline of the nearest Team A lineman.
2. A back is also the player in position to receive a hand-to-hand snap.
3. A lineman becomes a back before the snap when they move to a position as a back and stops.