Screening Posture

[NateWalker]

Can anyone find any information concerning a prescribed "posture" when screening? Situation : Player (fairly large) goes into his frontcourt, sets up at the top of the key and bends over placing his hands on his knees. He keeps this posture until his teammates cross halfcourt. They use him as a screen as he maintains this posture and does not move at all to initiate any type of contact. The defense cries that he is impossible to get around in that "stance" and it should not be allowed. I have found no info in my rule-book as to the legality of his posture in setting this screen.