Sit down on a flat bench and hold the dumbbells to your sides. Let your arms hang completely straight as you get ready for the initial shrug. This is your starting position.
Shrug/lift the dumbbells with your shoulders and traps all the way up until you get a good "squeeze" at the top. Hold for a fraction of a second at the top and then release the weight back down to the original starting position.
Finally, repeat the entire movement for the desired or prescribed number of repetitions.
Perform this exercise in a smooth and fluid motion
Don't lower the dumbbells back down too fast as this may result in injury; always be in control of the weight
SPECIAL NOTES & LEVEL of DIFFICULTY VARIATIONS
To increase the level of difficulty, slow down the movement or use heavier dumbbells.
This is a great exercise for the shoulders. It's comfortable to execute since it's done in a seated position on the flat bench (upright military bench is also fine). Keep in mind that the key to this exercise is not rushing it. Any jerking motion may cause you to pull a neck muscle or to injure your shoulders. Thus, proper pace is very important when executing this movement.
When you perform this movement make sure that your head is straight up looking into the horizon. Watching yourself in the mirror helps a lot as well because it allows you to see how far up you are "squeezing" your shoulders.