Another variation I enjoy is the one taught by Zuzana Light of BodyRock.tv.
Holding a bar or broomstick, your range of motion should allow you to maintain the the entire back of the shoulders, arms, wrists and hands on the floor as you perform this exercise. Otherwise, you the T arm position exhibited in the video.
Be sure to control the movement of the knees to the side, rather than allowing to drop into gravity. It is NOT necessary for the knees to touch the floor.
If you feel discomfort in your back, modify by keeping your feet on the floor as you rotate the knees to each side.
