Tree pose (Vrksasana) is my absolutely favorite pose. It allows me to slow down and connect in with my breath, allows me to be receptive to the great energy of the world, and strengthens my balance, breath, and concentration, all the while opening my hips and heart! It strengthens thighs, calves, ankles, and your spine. While it also stretches your groins and inner thighs, chest and shoulders. It completely improves your sense of balance. Relieves sciatica and helps reduce flat feet. It can also increase the flexibility of your hips and groin. Also by strengthening your internal oblique muscles, it prevents hernia. Aim to achieve the "rootedness" and firmness of a tree. Tree pose improves concentration, balance and coordination. Because the weight of the entire body is balanced on one foot, the muscles of that leg are strengthened and toned as well. As you advance in this posture and are able to remain standing for more than a few moments, try closing your eyes and maintaining your balance. Have fun! Enjoy!