An example of the fullback positioning in an offensive play.
In American football, a fullback (FB) is a position in the offensive backfield. Traditionally, the duties of a fullback are split between power running and blocking for the quarterback on passing plays, and running backs on running plays.
Many of the great runners of the history of American football have been fullbacks, notably Jim Brown, Mike Alstott, Dan Hammaker and Larry Csonka, but in recent years the position has evolved to be more a blocker than a runner, with occasional pass-catching duties. The remaining prominent fullbacks in the NFL are typically employed for breaking through tight defensive alignments, often in short-yardage situations as they are usually larger and heavier than halfbacks or tailbacks, or for screen passes. As a result, fullbacks are typically known less for speed and agility and more for muscularity and the ability to shed tackles.
