free throw shots

[just98]

One of the girls on my basketball team has a unique free throw warm up. when she is standing on the line she does almost a fake shot. she holds the ball at her chest and does a follow through check (not sure how else to describe it). she lets the ball roll off her hand and lets it hit the court picks it up and proceedes to shoot a free throw. is that legal. i guess what we are wondering is there any rules on what you can and can not do on the free throw line.

i dont know if that makes any sense to you, im not really sure how to describe it. if you get a chance could you let me know whats legal while on the line.