In the deep area, put the pool noodle behind, under your arms. Open your arms and rest your elbows and hands on the noodle. Keep your shoulders relaxed. Keep both your legs together, straight and your toes pointed.
Start with alternate sidekicks (flutter kicks). Make sure your knees remain still and only move your hips in low range of motion. Kick until you reach the end of the pool, then switch sides and go back until you reach the other end of the pool and so on. Or, you can kick in circles as shown in the second figure. If you are exercising in groups or if there is not enough space in the pool this method will work better for you.
Breathe regularly. Inhale through your nose. Exhale through your mouth.
Leg Kicks on Your Back
5 Tips To Improve Your Flutter Kicks