Stand with straight body, the hands are hanging freely on the side and hold each a dumbbell. Lift from this position the shoulders as high as you can, but don't bend the arms during the movement. On the highest point, make a short pause of 1 or 2 seconds before returning slowly to the initial position.

When training with a higher weight, make sure that you still do the whole movement!

The diagram shows the most used muscles on this exercise