Stand in the shallow-end with your feet shoulder-width apart and your arms stretched in front of your chest. Let your palms face forward.
Bring one knee high up as you lean your torso forward and bend your elbows at the same time. Keep your other leg still and your palms always facing forward. Extend the same leg behind, lean your torso back and extend both your arms in front. Repeat with the same leg continuously and then perform the same exercise with your other leg. Do not just swing your leg but keep your movement well controlled.
Inhale as you extend your arms and legs. Exhale as you bend together.
Use your core muscles as you bring your knee and your torso closer together. Use your chest and upper back muscles as you push and pull your arms (with the inside of your hand).
For better results you may use a noodle, aqua dumbbells or resistant footwear (provided they are not floaters).
Leg Kicks and Arms Swing