Good questions.
1.Regarding cut blocks: what you heard is generally correct; that's how it's called. Here are the gory details.
Cut blocks (blocks below the waist) are only allowed in the free blocking zone and only by players against opponents who are BOTH on the line of scrimmage at the snap. A linebacker cannot be cut. A fullback cannot lead with a low block. Conversely, A DB canot come take out the lead blocker with a low block (a tactic that gained popularity a few years ago). Legal cut blocking is only between linemen.
The free blocking zone extends three yards into the backfield for both offense and defense and four yards each side. It's a box 8 yards by 6 yards.
The second part -- the reason why it's really only legal immediately after the snap -- is the fact that the free blocking zone disappears when the ball leaves it. Because most teams use shotgun formation, the ball leaves it in a hurry, so there is only enough time to go low straight off the snap. Any delay -- any step back -- will likely mean the block is made after the ball is out of the zone, making the block illegal.
Technically, is the QB is under center, there could be a delayed block if the ball stays in the zone, but those situations rarely call for low blocks by linemen.
2. Intentional grounding in high school is VERY different than in NCAA or NFL. There is no tackle box,
Here is the criteria for IG:
- A pass intentionally thrown into an area not occupied by an eligible offensive receiver.
- A pass intentionally thrown incomplete to save loss of yardage or to conserve time.
The exception is intentionally spiking the ball (clocking, as it's now called) which must be done with a QB under center and must happen immediately after the snap.
We are usually pretty liberal in calling an eligible receiver "in the area," but if a QB on the run throws the ball onto the track, I'm usually flagging that, even if it goes right over the head (25 feet over the head) of a receiver. Doesn't matter if the QB is a yard inbounds.
The hardest part comes when a QB is being tackled and he throws the ball. On one hand, obviously he is trying to avoid a loss. On the other hand, if he's tryin to get the ball to an eligible receiver but the defender prevents him from getting off a good pass, then it could be nothing. That's where I earn the big bucks.