Hands and Knees position

[Y2Koach]

So the previous post got me thinking about different possible related situations:

- B1 is pressuring A1 full court. A1 has the ball in the backcourt by FT line. A4 gets on his hands and knees at half-court to set a screen. A1 is dribbling full speed headed towards the A4 screen. B1 running full speed trips over A4. Reviewing some of the rules references and applications in the previous post, how many of you guys would rule this a legal play?

- A1 is bringing the ball up court, dribbling towards the sideline, with B1 pressuring. B1 cuts off A1, directing A1 back towards the middle of the court. B3 had been reprimanded by his coach for picking up some ticky tack fouls by reaching when he goes to trap. So in anticipation of A1 reversing direction, B3 assumes the hands and knees position. A1 reverses direction at a high speed, takes 3 steps looking up court before he realizes B3 is in his way on his hands and knees. What is the call? What if A1 picks up the ball and jumps over B3 to avoid a major collision? What if A1 jumps over B3 to avoid the collision, but B3 begins to stand up at the same time (maintaining verticality)?