"Manduka" in Sanskrit means frog. The body in Uttana Mandukasana resembles an erect frog.
 

Position of Readiness
Sit in Vajrasana and keep your knees wide. Let the great toes touch each other and keep the body straight.
 

Steps
From a table position, slide your knees and feet wide apart. (Turn your feet outward and bring your feet in line with your knees for a more advanced stretch.) Interlace your fingers or place your palms down and bring your forearms to the ground, forming a triangle of support.
 Press your forearms downward to support your weight.
 Allow your pubic bone to become heavy, pressing downward.
 Press the crown of your head away from your shoulders and feel the lengthening of your spine.
 Press your tailbone back toward your heels.
 Allow micro movements to open your hips. (Rock your hips forward and back. Circle your pelvis. 

 Lift and lower your tailbone.)
 

Benefits

Mandukasana improves functions of all organs. It improves the lungpower, circulation in the walls of the chest and abdomen and tone of the abdominal and shoulder muscles. It also improves sciatica in some people. It plays important role in the treatment of constipation, diabetes and digestive disorders.
The asana acts especially in the joints of the knees and ankles improving coordination and fluidity of movement.

Precautions

People suffering from peptic or duodenal ulcer, severe back pain and cardiac problem, and patients who have undergone abdominal surgery should avoid this exercis.