This is one of the best aqua exercises for the chest and upper back muscles; First place one leg in the front and the other behind (this is important to keep you balanced on the spot), then bend your front knee until your shoulders are under the water.
Raise both your arms to the side, parallel to the bottom of the pool. With your arms straight bring them together across your chest all the way to the front in a semi-circular motion and then open again. Use the paddles/dumbbells/ gloves if available. If not, open your hands and try to feel the resistance in both directions as you open and close. Feel your chest muscles as you open and your back muscles as you close. Open with inhale and close with exhale. For your safety avoid hyperextension as you open your arms (i.e. Don’t bring your arms behind your shoulders). To increase the intensity try to squeeze the water out as you close.