NFHS Rules: I was watching a high school varsity game the other day and the following occurred. A1 obtains rebound on B's end of the count from a missed shot and B1 immediately takes up a guarding position. B1 is initially facing A1 then turns and runs laterally maintaining a position in front of A1 as he dribbles down the court. As A1 crosses the midcourt line into A's front court, A1 lowers his left shoulder and plows into B1 knocking him flat on his back before driving to the basket. The ref calls a block on B1. I would have called a player control foul. Was this actually blocking????

Spounds like a PC but who knows without seeing it.