The Flutter Kicks.
There are 4 Big Reasons why early development of a solid flutter kicks is so important to a swimmer, regardless of the level of swimming.
Big 1: A good and strong flutter kicks keep the whole swimming stroke together.
Big 2: A strong kicks gives a better position in the water.
Big 3: Developing a good strong kicks develop the core muscular strength.
BIG 4: IT MAKES YOU SWIM FASTER. PERIOD