Pratapana - Sanskrit for warm up practices - are part of yoga practice for me. There is nothing formulaic about it, yet there is a logical physiological sequence to follow. Yoga practice for some begins with sun salutations and this movement and sequence is designed to move the joints, stretch the spine, stir up circulation and allows lots of possibilities for adding variations. There are many days when Surya Namaskar (sun salutations) are too vigorous to begin my own practice, or my classes.
People with athletic or dance backgrounds know a good deal about how warming up the body leads into a safer and more productive practice. The body is only one part of yoga practice, and it does benefit hugely from sensitivity to the joints, circulation of energy and natural tightness of specific muscle groups. I recommend moving from the subtle and to more progressively dramatic movements of the spine, the rib cage, the hips, toes, neck, shoulders, well, the whole variety of body parts. The special aspect of this for me is that it is not with a focus on the hip that I would move the hip, but with a focus on the breath.
Breathing in expands the body, naturally moving and stretching more muscles and joints than I can name. Breathing out reduces the inner pressures, relaxing all those muscles and joints into a natural contraction. Yet the breath does much more than that. On a physiological level, the breath brings oxygenated blood into every cell and eliminates carbon dioxide and other "waste" products of the bodies functioning. On a psychological level, the breath draws energy and awakens a sense of fullness, openness, energy, sufficiency, expansion, and possibility with one conscious inhale; and releases, nurtures, calms, relaxes, opens and cleanses on the exhale. With a focus on the breath, all the Pratapana of spinal movements, opening and lubricating the shoulder joints, stretching of hamstrings and discovering mobility in the toe joints become a challenging and deeply moving practice of awareness.
With this level of engagement, your practice begins from the moment you put your attention in "yoga mode." Bringing attention to the breath will change your seat and your sun salutations. These are not exercises solely for the body, but experiences that offer the possibility of being fully present from the very moment that you breathe in and breathe out. The practice then can move in and out of Asana, and on and off the mat.