football

sounds stupid but, i figured if i was going to learn, i had to stop assuming i knew anything about football. so i went back to the basics.

here's what i learned about the football field...

a football field's dimensions are the following:

• length: 360 feet or 120 yards
• width: 160 feet or 53 1/3 yards
• end zones: 10 yards deep
• end line: a 6 foot end line border marks the back of the end zone
• team benches: placed along the restraining line between the 30 yard markers
• field numbers: 6 ft high by 4 ft wide
• restraining line: 6 foot line along the side lines that designate the closest non-players can be to the field.
• hash marks: in the NFL, they measure 70 feet, 9 inches from the sidelines and are 18 ft, 6 in wide (and, in fact, are the same width as the goal posts)
• goal posts: in the nfl and ncaa, they are 10 ft high and 18 ft, 6 in wide

uh, okay. i got that. i think.

at that point, i googled football field images and found one i really like. i won't show it here, but you can do the same and find an image that you like best.

we got a playing field. now, let's talk about what i learned about the game...

there are two teams of 11 players each. this is known as a "platoon" system.

it is legal to have fewer players on the field, but playing with more on the field is punishable by a penalty.

players must be designated with a uniform number between 1 and 99.

OFFENSE
the role of the offensive unit is to advance the ball down the field with the ultimate goal of scoring a touchdown.

the offense must line up in "legal formation". an offensive formation is considered illegal if..

• there are more than 4 players in the backfield, OR
• there are fewer than 5 players numbered 50-79 on the offensive line

interior offensive linemen are not allowed to move until the snap of the ball (doing so usually results in a penalty of some sort.)

backs and backfield 
the main backfield positions are the following:

• qb (quarterback),
• hb (halfback) /tb (tailback), and 
• fb (fullback)

quarterback role:
- leads the team
- throws the ball
- calls plays

halfback role:
- also known as the tailback
- carries the ball on running plays
- may also serve as receivers

fullback role:
- tends to be larger than the hb/tb
- primarily functions as blockers, although sometimes used as runners in short yardage situations
- often not used in passing situations

linemen
players whose primary function is blocking. these positions & their roles are the following:

• center (c) - snaps the ball to the qb
• guards (g) - lines up on either side of the center
• tackles (t) - lines up outside the guards

receivers

these include the wide receiver (wr) and the tight end (te).

wide receiver role:

- line up on or near the line of scrimmage

- they can catch, block, or be a decoy depending on the type of play

tight end role:

- line up outside of tackles

- they mostly receive and block

DEFENSE

prevents the offense from scoring by tackling the ball carrier or by forcing turnovers. consists of defensive ends (de) and defensive tackles (dt).

defensive ends line up on the end of the line

defensive tackles line up on the inside

the primary roles of the defensive ends and defensive tackles are to:
- stop running plays on the inside and outside
- pressure the qb on passing plays
- occupy the line so that the linebackers can break through

linebackers
they line up behind the defensive line, but in front of the defensive backfield. there are two types: 
- middle line backers
- outside line backers

linebackers are the defensive leaders and can call defensive plays.

their roles include:
- defending the run
- pressuring the qb
- guarding backs, wide receivers and tight ends in the passing game

defensive backfield
this is also known as the "secondary" and consists of cornerbacks (cb) and safeties (s).

cornerbacks (cb) line up outside the defensive formation and cover wide receivers.

there are two types of safeties:
- free safeties (fs)
- strong safeties (ss)

safeties line up between the corner backs, farther back in the secondary.

ultimately, these positions are responsible for stopping deep passes and running plays.

SPECIAL TEAMS UNIT
this unit executes and defends punts and kicking plays

field goals and kickoffs are performed by the following positions:

• placekicker (k or pk)
• long snapper (ls)
• holder (h)

punts and punt returners hold the following positions on a team:

• punter
• punt returner (pr)
• long snapper
• gunner

of the special teams unit positions, all seemed relatively self-explanatory to me except the gunner, which was the name of a position i'd never heard before. apparently, these guys line up outside the line and race down the field to tackle the player on the receiving team who catches the ball (the "punt returner" or pr).

and that's it. that's what i've learned so far. perhaps some of it will stick as i watch these games each week.