Yogasanas is about performing postures with awareness of your own body and breath. Without awareness of your breath, asanas do not serve their purpose of benefiting the body mind and soul. So, we are required to focus on breath during each activity of the asana – while shifting from initial position to final position and from final position back to initial position and even during final position of the asana.
Breathing out and breathing in during transition from initial position to final position is done just to facilitate the body to perform the asana with more easiness as well as improve the oxygen level in the blood and eliminate the carbon dioxide in the body which is responsible for toxicity in the body. When we bend forward just like in paschmitonasana, mandukasana, yoga mudrasana, we breath out just to facilitate the body to bend forward to allow the abdomen get inside. Similarly, when we bend backward just like in chakrasana, matsayasana, ushtrasana, the intercoastal muscles of the chest expands making internal atmospheric pressure reduced to allow the outer air (outer atmospheric pressure is high this time) go inside the lungs (the gas transits from the area of higher atmospheric pressure to lower atmospheric pressure). Therefore, to facilitate the body to bend and oxygenate the body, it is better to inhale while backward bending. On the same principle, when we come back from backbending asanas, it is better to exhale and therefore in the initial position, we should breath normally. Similarly, when we attain final position, it is not important not to hold the inhaled breath but to take normal breathing.
I think the concept of breathing is quite clear. If still any issue remains, I will be happy to reply and discuss further.
