From a health point of view, Dhanurasana is good for the digestive system. The chest expansion while doing this asana brings in course of time relief to asthma and other respiratory problems.
How to do Dhanurasana?
Lie down flat on your abdomen.
Ensure that your forehead is placed against the floor and that your legs are close together.
Bend your legs at the knees and bring your feet up behind you.
Stretch your arms backward and grasp your ankles.
Inhale. Lift your head off the ground and simultaneously lift your thighs upwards.
Your body should be arching upwards now.
Maintain the posture for 10 seconds at the outset.
As you practise, you can increase the timing to about one minute.