This is a non-standard Open Focus exercise that I like to practice.
As you know, space awareness is the heart of Open Focus practice. It is the quickest way to generate alpha synchrony in the brain.
It was easy for me to become aware of space during OF exercises when I was sitting still on a chair. On the other hand, it was always quite difficult to feel space outside and inside my body during my everyday activities (walking, driving, swimming).
I came up with following technique.
You could try it now.
Firstly, realize that your body is full of space (there is space between atoms that the body consists of and, more importantly, every atom is 99% filled with space). Watch this clip if you need to see a proof of this link.
Now look at your right hand and realize that your hand is full of space which is inside and between atoms. Your hand is also surrounded by space (which seems more obvious)
Now move your hand a few inches to the left.
Ok, you moved atoms of your body but what has happened to the space which is inside and between them.
Has it moved? Can space move when it is not an object?
So, in order to become aware of space when you are physically active imagine that only the atoms of your body are moving but the space around and inside you stays still. Imagine that space inside and outside of you is like a still background which cannot be moved. It means that from the atoms point of view they stay still to each other but space around them is moving.
Just try it.
For me it felt as though I was completely transparent and very light.