Stand with your feet shoulder width apart, your back straight and your abs drawn in.
Hold a dumbbell in your right hand with your palms facing up.
Raise the dumbbell over your head and slowly lower the dumbbell in an arc behind your head, so that the dumbbell lines up with your spine.
Slowly raise the dumbbell back up to the starting position.
Switch arms and repeat.
Note: Keep your elbows close to your head during the exercise