Grinding

Sit in long sitting posture with legs stretched out on either side as much as possible.
Now join both the hands with the fingers of both hands tightly clamped.
Now bend forward take the hands near the left foot and then to the right foot and then go sideward and bend backwards as much as possible and then again reach the left foot. This completes one round .The movement should be from hips and not at the hands. This gives a rotation to the hip joint.
Repeat it on the anticlockwise direction.
Initially practice it for 5 times and then you can increase