Sajdah (as muslim call it by its arabic name) or Prostration, is a position of complete humility in front of the Creator and the closest one can be to God; the message it carries is: cut off from the world around us for a few brief moments of complete submission and worship. It is also a good position for meditation on God.
It is said by Prophet Muhammad (peace be upon him) that any person is more near to God in the position of prostration than anything else. And Prophet encouraged to ask to God in prostration because God loves it and if He wills accept the prayer.
From Sufi idea, it is only during prostration, our heart is above our head. And Sufi idea always encourage to follow heart, not head. Because head might cause you to go in wrong path, but a pure heart never does that. And heart being the symbolic throne of God (although not the physical heart), which symbolize that we are putting it above all, even our brain. Also it acknowledges the limitations of our brain. The humility of a man in front of God, which is expressed by prostration can not be expressed in any other ways.