Dumbbell Side Bends

Stand with your feet slightly wider than shoulder width and grab a dumbbell in your right hand.
 
Place your left hand behind your head and bend your torso to the right until you feel a good stretch in your left oblique muscles, being sure to keep your hips stationary. Bend your torso back to the left as far as possible and then return to the starting position.
 
The entire motion should be done in a smooth, controlled manner that lasts about 2 seconds to each side, with the downward movement no faster than the upward.
 
After completing your reps for one side, reverse sides and repeat.