The Half locust Pose
Lie on your abdomen with the chin touching the floor. Push the chin a little more forward to bring the throat parallel to ground.
Then make fists of your hands and place them under the thighs with elbows close to each other. Keeping the hands beneath the body and chin pushed forward, inhale and raise your right leg up as high as possible.
Remember to keep your hips firm on the floor and the knees straight. Now bring down the leg gently and repeat the process with the other leg. You can keep on holding up each leg for up to 15 seconds.
The Ardhasalabhasana or half locust is only a preparatory yogic exercise for the yoga posture or asana Poornasalabhasana