Stand in the shallow-end and hold the dumbbells with your elbows bent about 90 degrees in front of you. Let your palms face inwards as you hold the dumbbells in vertical position, under the water.
Push your forearms out and in together in a comfortable range of motion. Don't try to reach out too far. Keep your forearms level, parallel to the bottom of the pool, and your elbows always firm by your side. For maximum benefit, the dumbbells should stay under the water all the time.
Rotate out and in once with inhale and once with exhale.
Feel your shoulder muscles as you push the aqua dumbbells on both sides
You can perform the same exercise without aqua dumbbells or other resistance tools. Creating resistance with your hands can make a good exercise too.