This video explains some common problems with kick technique in each of the swimming strokes. If your kick isn’t going anywhere, this video might help you discover why.
Your legs should be powerful but loose when you kick. If your joints are stiff, any power you put into the stroke won’t flow. You may be tense because you are afraid or because you are overthinking and trying to perform a perfect technique. Sometimes, it helps to relax and loosen up and not be afraid of getting it wrong. If you are afraid of the water itself, then be patient. Know that you may not travel very far or fast until you have overcome your fear of the water. Make sure you learn safely.
Many people have stiff ankles and this can make the kick ineffective. A lot of the power in a kick comes from the flexing and pushing of the foot against the water. If you have stiff ankles, try doing some gentle stretching at home, take part in a yoga class or simply sit and flex your ankles whilst sitting in a chair.
It is not just the accurate movement of the legs that makes an effective kick. Getting the pace right is important, particularly in breaststroke. The power in a breaststroke kick comes from pushing the feet away from the body. When you draw your feet back up again, this is a resting phase and it should be gentle. If you draw your feet back up vigorously, then you will be pulling yourself back and cancelling out a lot of the forward motion you got from kicking your legs out.
When you overthink a technique, you don’t let the movement flow. Understand the technique, then practice it without continually analysing what you are doing. Try and let your movements become natural and flowing even if they aren’t absolutely perfect.