Vīrāsana

Vīra means a hero or warrior. 

How to perform

Kneel on the floor.  Keep the knees together and spread the feet apart 18 inches.

Rest the buttocks on the floor but not body on the feet.  The feet are kept by the side of the thighs, the inner side of each calf touching the outer side of its respective thigh keep the toes pointing back and touching the floor.

Keep the wrists on the knees, palms facing up.  Join the tips of the thumb and forefingers. Keep rest of the fingers stretched.

Stretch the back erect.

Stay in this position as long as you can, with deep breathing.

Then rest the palms on the knees for some time while keeping hands tight.

Now interlock fingers and stretch the arm straight over head with palms facing upwards.

Stay in this position for a minute with deep breathing.

Breathe out, release fingerlock, place the palms on the soles and bend forward and rest the chin on the knees.

Stay in position for a minute with normal breathing.

Breathe in, rise the trunk up, bring feet forward and relax.

If you cannot do this pose as described, you may keep feet one above the other and try the same āsana.  Gradually you can increase distance between your feet until buttocks rest on the floor.

Note: This pose can even be done immediately after taking food and will relieve heaviness in the stomach.

Effects
This pose increases flexibility in the legs.  Persons suffering with pain in the heels will get relief. 
This pose cures rheumatic pains in the gout and flat foot.  The spurs will gradually disapper.