A mindfulness of the direction of the movement of breath can be necessary to realize support for the lower back. This is because the ligaments that support the lower back in flexion are different from the ligaments that support the lower back in extension (more about this later).
Gautama the Buddha described mindfulness of in-breaths and out-breaths as his way of life, both before enlightenment and after (Sanyutta-Nikaya, text V, Pali Text Society volume 5 pg 280 & 289). He began with a focus on the body, as follows:
For me, these observances do not come naturally, except as I recognize the movement that accompanies my sense of physical location. The more I recognize the existence of movement even when I am holding still, the more necessary a mindfulness of breath becomes to my sense of balance.
The connection between movement and breath is subtle, and I gratefully acknowledge the work of Moshe Feldenkrais as my inspiration in this regard. Feldenkrais noticed that most people tend to hold their breath slightly as they get up off a chair, and he suggested three movements that could be practiced to allow a continuity of breath in the transfer of weight (see Feldenkrais’s “Awareness through Movement”). In essence, Feldenkrais’s exercises set up mindfulness of movement in three directions; he did not expect anyone to generate physical movements in these particular directions as they got up off a chair, but he expected that once mindfulness of these movements was established, a shift of weight could occur without disruption to the movement of breath.
Gautama the Buddha’s way of life was a mindfulness that included the experience of his in-breath or out-breath, yet his enlightenment concerned the nature of suffering. He invited his first followers to “practice the life of purity to bring a complete end of suffering” (Vin I 21), and he taught four truths that began with the definition of suffering as grasping after self.
By all accounts, the end of suffering is realized out of necessity. Thich Nhat Hahn once said that “to suffer is not enough”; apparently the more we are in touch with our own well-being, the more necessary making an end to suffering becomes. The Gautamid’s way of life kept him in touch with his own well-being, and allowed him to realize the end of suffering as a necessity in the course of a breath in or a breath out.