There are THREE fundamental legal types of RUN blocking NOT counting draw blocking from retreating pocket:

1) Zone blocking - essentially all five O-Lineman take on a hat L/R or straight in front, is hat on hat, and when using wide splits it can be very effective until its becomes too predictable. This is the FIRST or FRESHMAN LEVEL blocking that is usually taught and mastered.

2) Trap Blocking - which is essentially when any two lineman X paths (one over and the other under) so that the drive on two Defenders comes from L & R (inside out) creating a big gap between them. This is especially effective if the MLB has two gaps and decides to cover the wrong gap, or when the OLB stays course and gets caught up in the wash-down to his L/R due to the trapped D-Lineman being pushed into his path. This is essentially Blocking 201. When added into the ability to effectively zone block, an offense becomes significantly more unpredictable. We RARELY saw any of this from Robert Anae's offense under Bronco when he was at BYU. His current Virginia team is much better at all types of blocking EXCEPT pass blocking (not really related to this discussion, but 2J's lines give up over 4 sacks a game - same 'ol same 'ol).

3) Pulling Lineman in various numbers and directions, and position groups. When you add this element, and it takes speedy (quick footed and well balanced) O Lineman, you add the best of all worlds. Not only does the effect of a pulling linemen or even two add the trap element to creating holes, it can come from ANY O-lineman and so it often leaves a D-Lineman completely out of position and stuck behind his own trapped D-Line and LB group. We see this happen when we see a DE stunting to the inside of a tackle and a Guard comes backside to block out the linebackers and a wide receiver takes out the DB/Safety in his zone.

One of the great things about utilizing these schemes in variety at anyplace on the field and on any down and distance combination is that it makes preparing a defense darn near impossible. When you watch really great offenses execute, its most often because the OC is adept at utilizing changing the blocks far more than trickeration. In the McChesney series when he rushed three times and scored, it is true, USC's D-line was gassed. But, the blocking awareness of the logical gap and shoulder reads were critical as well. McChesney was able to plow through the A Gaps because the NT had given away his lean favoring his right shoulder. Sometimes you wont know why unless you are astute as an O-Lineman and are watching the opposing players closely after every play. It could well be that the NT was favoring his left shoulder (possibly injured and hurting ???) and Pay/Tokuafu noticed? Don't really know, but by favoring the hit on his left shoulder to the center, it allowed the BYU left guard to drive block his MLB off the A Gap and that's where Cheese ran on all three plays. Sometimes great blocking is in the little things a player or his coach notices about his opponent on the field.

Bottom line lesson - ZONE BLOCKING Teaches Technique with upper body. Trap Blocking teaches the power of driving and opening an actual hole. Pulling adds a elements of surprise and hiding the power of the trap from the second level. when a team's O-Line can do ALL THREE of these things, it can be dominant. BUT, you need an equally prepared OC that knows the down and distance tendencies need to remain completely unpredictable. I think BYU zone blocks a little too often and underutilizes its excellent trapping and pulling capabilities, especially on 1st and 2nd downs. I like standard trap blocking by Guard and Center or Guard and Tackle on perhaps 40-50% of 3rd and short plays, and mixing it up as to who carries the ball or even if it remains a run. The less predictable an offense is, the more successful it will become.