Trikonasana

TRIKONASANA: "Trikona" means 'triangle'.  When you start this exercise your body takes the shape of a triangle and so the name.

Method:  Stand straight. Inhale.
Keep the legs 3 to 4 feet apart from one another.  The knees should be straight.  Raise both hands to the shoulder level. Turn right foot to 90  degrees to the right side and left foot slightly to the right side. Align the right heel with the left heel. Exhale slowly and simultaneously lower the right hand palm in order to place the palm on the  ground and raise the left hand upward, and see the tips of the left-hand fingers.  Continue in this position for at lease one minute while breathing normally.Repeat the same thing with the left foot.

This exercise strengthens the muscles of the back, hips, and legs. 
It cures backache, shoulder pain and joints pain. It also strengthens ankles, knees and shoulders.