Ive been wanting to be a linebacker in football for some time but dont have a clue about it, Can you tell me what it is? 
Well, they are part of the defense and their job is to line up three yards behind the line of scrimmage, behind the linemen and back them up.
Oh ok, That sounds tough. Are there a lot of injuries with being a linebacker? 
Yes because they tend to hit hard during running plays.
Ouch, thats a part of what scares me about some positions in football. Is there more than one linebacker on the field at one time?
three-point stance" or "four-point stance" before the ball is snapped).
The goal of the linebacker is to provide either extra run protection or extra pass protection based on the particular defensive play being executed. Another key play of the linebacker position is blitzing. A blitz occurs when a linebacker acts as an extra pass rusher running into any exposed gap. When a blitz is called by the defense, it is mainly to sack or hurry the opposing offense's quarterback.
Linebackers are often regarded
Linebacker
A linebacker (LB or backer) is a playing position in American football and Canadian football. Linebackers are members of the defensive team, and line up approximately three to five yards (4 m) behind the line of scrimmage, behind the defensive linemen, and therefore "back up the line". Linebackers generally align themselves before the ball is snapped by standing upright in a "two-point stance" (as opposed to the defensive linemen, who put one or two hands on the ground for a "