The air is a powerful element. The air is so strong that it can even blow away the mountains. There are regular experiences of watching the rocks, boulders rolling down after being blown out by the air.
'When the respiration is moving, the mind is also moving. When the yogi restrains the breath, the mind is also restrained.' The yogi gets the steadiness of the mind.
The gross air does not move all over the body. It is only the subtle air that moves all over the body.