If you are attempting to learn how to deepen your backbend to the point where you can stand up and drop back from Urdhva Dhanurasana, then be sure to give yourself time and patience to develop the strength and flexibility needed. Rushing the movement will only increase any fearful sensations and sometimes comes at the expense of good solid technique. The first thing to consider when attempting to stand up and down from backbend is whether your backbend is ready for such a motion. First be sure that in Urdhva Dhanurasana your arms are straight, your lower belly is drawn in, the feet are parallel, the spine is lifted and fully extended and that you are able to have the weight evenly distributed between your feet and your hands. Then see if you can walk your hands closer to your feet while keeping the heels firmly planted on the ground, without compromising the structural integrity of the posture or the stability through your legs. If you are able to do these movements with ease then you are ready for the next step. Stand at the front of your mat with your feet hips width apart. Place your thumbs on your sacrum and begin thrusting your pelvis forward over the solid foundation of your feet. Next lift the lower belly into the body while lifting the spine up and out of the pelvis. Drop your head back while lifting the chest and sternum and look for your mat. Breathe freely and deeply. Try to lift your arms over the top of your head while dropping your head back further and looking for your mat. When you can see you mat and keep the arms outstretched you can safely bend your knees while keeping the feet firmly planted on the ground to drop back to your mat.
Don’t rush the movement. Hang over upside down gazing at your mat for ten to twenty breaths if you need to develop the strength it takes to support the full range of motion. Many students feel intense fear when they hang over backwards along with severe constriction of breath. This is something that improves the more you practice. Be conscious about creating length between the vertebrae, spaciousness in all the joints while avoiding any temptation to force the body into a posture it might not be ready for. When fear arises do your best to train the mind to remain calm by breathing deeply and focusing on the inner body. With practice even this challenging motion will be easy to perform.
See the movement on my YouTube channel below: