The Proud Warrior pose is also known as Warrior I.
Daksa once celebrated a great sacrifice, but he did not invite his daughter Sati nor her husband Siva, the chief of the gods. Sati, however, went to the sacrifice, but being greatly humiliated and insulted threw herself into the fire and perished. When Siva heard this he was gravely provoked, tore a hair from his matted locks and threw it to the ground. A powerful hero named Virabhadra rose up and awaited his orders. He was told to lead Siva's army against Daksa and destroy his sacrifice. Virabhadra and his army appeared in the midst of Daksa's assembly like a hurricane and destroyed the sacrifice, routed the other gods and priests and beheaded Daksa. Siva in grief for Sati withdrew to Kailas and plunged into meditation. Sati was born again as Uma in the house of Himalaya. She strove once more for the love of Siva and ultimately won his heart. The story is told by Kalidasa in his great poem Kumara sambhava (The Birth of the War-Lord).
This asana is dedicated to the powerful hero created by Siva from his matted hair.
In this pose the chest is fully expanded and this helps deep breathing. It relieves stiffness in shoulders and back, tones up the ankles and knees and cures stiffness of the neck. It also reduces fat round the hips.
It relieves backache, lumbago and sciatica. It strengthens the back muscles, tones the abdominal muscles, relieves acidity and improves digestion. It strengthens the bladder and corrects a displaced uterus. It relieves mentrual pain and reduces heavy menstruation.
Note: Please perform the yoga under the guide of a certified yoga teacher especially for beginner. You are at your own risk and responsible if you perform on your own. Whatever provided here is just act as an information.
Source from Light on Yoga by B.K.S. Iyengar
Yoga - The Path to Holistic Health by B.K.S. Iyengar