The most important yard in any football game is the yard that separates the offensive and defensive lines. The long passes and exciting runs that bring ever-increasing crowds to pro games depend upon control of this yard; if the offensive line cannot dominate it the quarterback spends a long afternoon on his back, and the runners join him whenever they are unfortunate enough to be handed the ball. Time was when the linemen, who needed little more than strong bodies, labored in relative obscurity and for peons' wages. Agility, physical or mental, played little part in their afternoon's work. But today they think and move fast, and for these very good reasons they are very well paid for their work.

Applying power at the point of attack
The power sweep pictured at the right and diagramed below is designed to create an alley for the ball carrier by sheer blocking force. Both guards (62 and 66) have pulled out to lead the runner, the flanker back (circle at the far right in diagram) has turned in to cut off the defensive back. When the runner hits the alley, one of the guards convoying him will be ready to take out any defender who has survived the primary blocks used to set up the corridor down the sideline.

Using deception to create a hole
The play diagramed above is almost the opposite of the power sweep. It allows the offense to set up a flow of defenders in one direction, then to strike counter to the flow, giving the offensive linemen good blocking angles on the defense and using the defenders' own momentum to beat them. The left halfback (29) creates the flow by going into motion to his right; after the quarterback fakes a hand-off to 29, he gives the ball to the fullback (33), who slants to his left, away from the original direction of the play.

Protecting the passer: key to success
The wonderfully accurate passers who direct the fortunes of professional football teams are at the mercy of the guards and tackles who block to protect them. This blocking is no simple assignment, and it is complicated by defensive maneuvers such as the one diagramed below—known in football as the red dog. Here a linebacker (black square B at left) abandons his usual assignment (dotted arrow) in favor of a direct assault (heavy arrow) on the quarterback. He is the red-dogging player in this case; it could just as well have been the middle linebacker (C, whose other possible routes are shown by dotted arrows) or the right linebacker. Defensive signals, which help keep the assignments straight, are called by one of the three linebackers.

Trap for the eager
Here is one of the oldest plays in football—the trap. The key man in the picture at right and in the diagram above is the left guard (68). In this play he is trapping the defensive left tackle. The right guard, playing head on the tackle, has pulled out to block downfield, giving the defender what seems to be a clear route to the ball carrier (heavy black line). But as the defensive tackle barrels happily across the line of scrimmage the left guard suddenly hits him from his blind side—opening a hole in the line and teaching the tackle a hard lesson.

Preserving the man who wins championships
Pass-protection blocking very often means the difference between a club's winning a championship and finishing deep in the second division. It is a very special art, requiring from the blocker enormous agility and persistence. In blocking for a running play, the lineman is asked to stop a defender only for the split second it takes for a ball carrier to enter and leave his particular zone. To protect the passer for the three and a half to four seconds needed to launch a pass, the blocker must use his ingenuity and strength to stay in contact with the defender steadily during that entire time. This can mean, in terms of modern pro football, butting heads with a mean 250-to-280-pound tackle for what sometimes seems like an eternity.