Sit upright on a flat bench back holding a dumbbell in each hand resting on your thighs. With momentum, lie all the way back and simultaneously raise the dumbbells up until they level with your upper chest. The palms of your hands should be facing forwards, with your elbows just below your shoulders and bent at roughly 90 degrees. This is the start position. As you exhale, push the dumbbells up and directly over your head by extending your arms until the dumbbells almost meet at the top of the movement. Think about initiating the push from your elbows and squeezing your chest at the top of the movement. Slowly return to the start position inhaling as you do so. Repeat for the required number of reps (or time).