I often take Virasana pose when seated for meditation after a long day of standing and walking about the city. I find that this pose is most calming and provides relief to my thighs and knees. This is a great posture for pregnancy, as it helps to circulate blood through the legs as it gets sluggish near the second to third trimesters.
Kneel on the floor (on a folded blanket to pad your knees, shins, and feet if necessary), with your thighs perpendicular to the floor, and touch your inner knees together. Slide your feet apart, slightly wider than your hips, with the tops of the feet flat on the floor. Angle your big toes slightly in toward each other and press the top of each foot evenly on the floor.
Exhale and sit back halfway, with your torso leaning slightly forward. Wedge your thumbs into the backs of your knees and draw the skin and flesh of the calf muscles toward the heels. Then sit down between your feet.
If your buttocks don't comfortably rest on the floor, raise them on a block or thick book placed between the feet. Make sure both sitting bones are evenly supported. Allow a thumb's-width space between the inner heels and the outer hips. Turn your thighs inward and press the heads of the thigh bones into the floor with the bases of your palms. Then lay your hands in your lap, one on the other, palms up, or on your thighs, palms down.
Firm your shoulder blades against the back ribs and lift the top of your sternum like a proud warrior. Widen the collarbones and release the shoulder blades away from the ears. Lengthen the tailbone into the floor to anchor the back torso.
At first stay in this pose from 30 seconds to 1 minute. Gradually extend your stay up to 5 minutes. To come out, press your hands against the floor and lift your buttocks up, slightly higher than the heels. Cross your ankles underneath your buttocks, sit back over the feet and onto the floor, then stretch your legs out in front of you.
Stretches the thighs, knees, and ankles
Strengthens the arches
Improves digestion and relieves gas
Helps relieve the symptoms of menopause
Reduces swelling of the legs during pregnancy (through second trimester)
Therapeutic for high blood pressure and asthma