I find often that the best posture for prayer is prostration. I lay flat on my face when I was ordained priest, flat on my face on Good Friday and during lent and at other times I make the ancient prostration with my head to the floor. Orthodox and Coptic practice preserve this anient form of prayer and how sad it is that it is Muslims that are more noted for this prayer before the great mystery.
I stand, I bow low, I prostrate and then I stand up again. This, when words dry to ashes in my heart brings an experience of liberation. This prayer with the body is I feel a form of profound silence.