Instructions
Stand with your back against a wall or a low lying ledge, with the swiss ball out in front of you. Lean on to the ball and with your feet out wide and against the wall/ledge, position your body so that only your hip/groin region is on the ball. Place your hands by your ears and keep your elbows out wide. Lower yourself down onto the ball, but only to the point where your lower back can stay stable and that it doesn't round at the bottom of the movement. Raise yourself back up as far as you comfortably can without causing strain in your lower back, bringing your arms back behind you for a chest stretch. Place hands by your ears again before repeating the movement.
Tips
The prime movers of this exercise are the hips, glutes and hamstrings. Not the back as the name suggests.
When first beginning this exercise it might be best to extend your torso up only until your torso is inline with your legs. As you get stronger and more comfortable with the exercise, you can reach back further.
