NFHS: LGP or not? PC or block?

[bucky]

1) Turnover by Team B near division line. A1 gathers the ball and heads upcourt. Immediately after A1 gets control, B1, 10 feet away and in front of A1, is facing A1. B1, turns away from A1 and sprints to get back on defense. A1 is slow while B1 is fast. B1, facing away from A1 the entire time he was sprinting back, gets to the low defensive block, stops, and is still facing away from A1, with his back to A1. A1 continues his fast-break and plows into the back of B1. Ruling?

2) Same play except B1 never faced A1. Ruling?



Side note: When we discuss Legal Guarding Position, does distance matter? For example, A1 is guarding B1. A1 is 30 feet away from B1 and facing B1. Is A1 considered to be in legal guarding position?