Flash: just general reflexes. Like reaction time when someone throws something at you or blocking (in my case it's trying to block my brother's shadow boxing lol)
Bob: isn't that just an exercise? will you get better at it the more you do it?
If your holding a 30cm ruler then u know when ur going to drop it so u will know. The point of it being a reflex and fast is that you don't know, u just react.