Can someone explain (sorry, very basic question)

[SamG]

Originally Posted by JRutledge

It is only a false start when the simulate the snap. Players can shift, motion and do all kinds of things even if they are interior lineman before the snap. And it is reasonable when audibles are made to allow the players to hear the call or the change. Only when the lineman put their hand down in the "dirt" are they really restricted from moving off the ground with their hand. Nothing in the rule says they must be totally still or considered in motion if they move their head or if they move a hand. If that is the case then the center would never be able to make signals which they do often when players come to the line for a possible blitz.

Not sure I answered you question totally, but it is a myth that everyone must be totally still. Just like we see the QB move around and make signals to get the snap.

Peace

Thanks for the answer. I guess what throws me off is when you see (generally) a lineman "flinch", and the flag is thrown.