Dhanurasana (Bow pose)
     This posture resembles a bow, so its name is Dhanurasana.
1. Lie down on the stomach.
2. Stretch the hands alongside the body.
1. Bend at the knees, touching the feet to the buttocks.
2. Catch hold of the ankles by the hands.
3. Close the mouth. Bring the ankles down and forward so that the chest and thighs are raised higher and higher.
4. Only the weight of the body will rest on the navel.
5. Raise the hind and upper part of the body.
6. Bend the body into a bow shape.
7. Retain the pose for a while.
8. After one week, rock the body forward and backward so that the entire system gets a massage.
  Thirty seconds up to five minutes. While catching hold of the ankles and straining, breath in, and while rocking forward, breath out
Dhanurasana is the combination of salabhasana and bhujangasana.
That is why provides he benefits of both of those asanas.
3. It makes the entire back elastic and strengthened, it cures constipation and diarrhea, reduces obesity and strengthens the muscles of the hands and legs.
4. It gets rid of flatulence, and gives a good massage to the chest and stomach.
  Avoid if suffering from slipped disc hernia, or high blood pressure.