Coach: The only kick-off I have taught since about 1980 is the "ABC":
B is the main, regular (deep) kicker. A is a pop-up on-side kick (OSK) specialist, who practices only one kind of kick -- he tops the ball, which ideally goes off the ground and up into the air in front of R1-R3. C is a sidewinder -- he kicks OSK's that scoot along the ground off the side of his foot, arriving 10 yards downfield in front of (ideally) L3 and L4.
We send the kick signal into the huddle with one of the players -- "A, B or C" is all we call. "B" is the regular deep kick-off, although we can designate "B Right" or "B Left" to kick away from a fast return man. (Note: We have also used a "B2" kick-off, where B kicks through the middle of the ball at the receiving man right in front of him, a screaming line drive if done right, with our cover guys converging for the rebound.) On the B kick, A and C cross behind B and carry out regular coverage duties. You can assign your normal men to safety and headhunter duties on the B kick -- it's business as usual.
When "A" is called, B approaches the ball as usual, but A cuts in front of him and delivers his specialty kick, which if it works right bounces off the ground and arrives 10 yards downfield just when R2 (a good vertical leaper) does. R1 and R3 block receiving team members who are near the ball -- if there is only one, they double team him (5 in the diagram). The kicker's technique is simple. B will tee the ball up almost vertically; when A kicks it, he aims for a point between the top of the laces and the stripe on top and kicks it at about 75% power, aiming for the zero in the number 50 on the field. It will usually bounce low once or twice, then pop up high in time for R2 to leap for it.
"C" Is similar -- B fakes a kick, but C scoots in front at the last second and delivers his "grass-cutter" OSK -- a classic "sidewinder" low OSK technique to keep the ball on the ground, traveling hard and fast. He should aim for the far hashmarks. L1, L2, L4 and L5 all block the nearest receiving team member, doubling if there are only one or two nearby (1 and 2 in the diagram). L3 heads straight for the ball and falls on it after it travels the necessary 10 yards.
People have often complained that they don't have time to train three kickers, but that misses the point. A and C are almost always taken from "regular" players -- we hold try-outs early on in spring or pre-season practice, working extra time with any kids who show talent and the inclination to work hard to learn a new skill. The point is, it is the ONLY kicking skill they need to learn -- one type of delivery, which can be learned surprisingly quickly. I have never coached a C or A player who didn't put in extra time before and after practice to perfect their one kicking skill. This also means they are 100% functioning members of the "B" kick-off team, not just extra kickers who could only be used as safeties.
With ABC in our arsenal, we felt prepared to OSK at any time. The beauty is, we would often only show A or C early in a season, saving the other for a surprise -- which means we had an effective OSK ready even when the receiving team was lined up to grab the other kind. If they are ready for C, A will tear their hearts out, and vice-versa.
wisnia1337