Bent Leg Hold
Use a chair with sturdy arms, or parallel bars. Grip the chair with straight (or slightly kinked) arms. Brace your upper body, and lift your knees up. At the top, your thighs should be at least parallel to the ground. Over time, as this hold gets easy, try to lift your knees higher for a better active stretch. Keep your feet and legs together and try to breathe normally during the hold.