Take a barbell and stand with a straight body, the arms are hanging freely in front of you. 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