To achieve this asana, begin in a seated position with the legs extended forward. The palms or the fingertips (if the palms don't reach) should be rested on either side of the body. The upper-body should be extending upward through the crown of the head, and the back should be completely perpendicular to the ground (as though sitting against a wall). If this is not possible, one may want to use a block underneath one's sitting bones to reduce the intensity in the hamstring muscles. The entire core should be engaged and ujjayi breath active throughout this asana. The legs should be squeezing together, and the toes should be pointing inwards toward the body. It may even be possible to create space between the heels and the ground by activating the leg muscles.