Stand on your left leg with the right leg behind you with a bit of weight on your toes for balance; both knees are slightly bent. Place your hands behind head.
Pull your abs toward your spine and keep your back straight as you hinge forward from your hips until your torso is almost parallel to floor.
With a flat back, press through your left heel and return to standing as you twist your ribs and shoulders to the left. Your pelvis should stay still. This completes one rep.