“The feeling of the breath” refers to the feeling of energy or prana moving in the body. The principles underlying each classic asana has a particular implication to the movement of prana in the body. A teacher who understands asana from the point of view of whole-body feeling and the movement of prana can adopt classic asanas to the needs of each student. The student thus enjoys and benefits from the principle that it inherent to each particular posture.
The key to right practice and the appropriate variations of an asana is to maintain the link between breath and body. Via the breath we can be with the whole body and observe the unfolding of an asana. Rather than struggle with the body in an asana, we monitor the asana with the number of breaths and the breath ration (inhale, pause, exhale, pause) that is appropriate for us. If our breath is smooth and has continuity, the asana will e beneficial.
The breath is one of the means by witch we vary asanas. There is a natural elasticity in the body that is enhanced as we breath in asana practice. As the body moves the breath moves, and as the breath is stationary the body is stationary. Thus the breath and body becomes one movement, one process, and that is a very powerful yoga. Maintaining this link between breath and body, particularly in lengthening the exhale and pausing after the exhale, has more significance to the purpose of yoga than achieving a classic asana for its own sake. the breath has a very important role in asana practice. We should not compromise the easy flow of the breath to achieve the asana.
The breath is one of the best means for observing yourself in your yoga practice. How does the body respond to the breath, and how does the breath respond to the movement of the body? The breath should be your teacher.
T.K.V. Desikatchar – The Heart of Yoga. Developing a Personal Practice – 5 Asana Variations
this is what yoga is about
this is what vipassana is about