This asana is also known as Upward Bow Pose (Urdhva Dhanurasana). Urdhva means upwards. Dhanu means a bow. In this posture the body is arched back and supported on the palms and soles.
This asana strengthens the muscles of the abdomen and thighs. It makes the back and hips supple, improves memory, and is said to relieve afflictions of the trachea and larynx. It brings very good flexibility to the spine, stimulates and activates all parts of the body. It strengthens the arms, shoulders and legs. Only those who are free from any disease can perform this asana.
Advanced students can try to come into the Wheel from a standing position. This will give you a complete backward bend to all parts of the back, neck, shoulders, and limbs.
When you feel that you can stand firmly and comfortably in the Wheel, many variations await you. These are designed to bring an even greater increase of strength and flexibility to the spine, shoulders, and upper back. Example of one of the variation is to bring both legs together follow by stretching and straighten the both legs with knees lock instead bend and arms straight too. (see picture below)
Another example of variation is to raise one leg up. In addition to the benefits derived by the Wheel, this beautiful asana develops a sense of balance and gives grace and poise. (see picture below)
Note: Please perform the yoga posture 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 Yoga Mind & Body - Sivananda Yoga Vedanta Centre
Light on Yoga - B.K.S. Iyengar