The kick may not provide the propulsion that the rest of the body does, but it plays a crucial role in how the body moves in the water. I believe there are 3 factors that contribute to a efficient kick:
*Kick should be low effort/be low drag
*Timing of the kick should aid in body rotation
*Velocity generates from the hips, not knees
One of the biggest improvements I see each and every "non competitive'' swimmer has, is their ankle flexibility. As a triathlete, you spend SOOO much time on the road in a dorsi flex state. This creates a position, flexing your toes back to your shin, makes life hard. The toes act in breaking the water and takes away any potential velocity with your feet.
Think of your kick, like a whip. All of the velocity generated in the kicking motion ends up at the end, or the feet. The more flexible the ankle, the faster the water moves, the faster you go forward. But how do you create more velocity?...Swing the whip harder. By igniting the kick with your hips, not your knees, you allow your leg to be used as a longer lever. This longer lever will allow for access to the potential water to be moved.
At the very end of the whip, the motion is over and time to pull back. As soon as your ankle snaps down and pushes the water behind you is the opportune time to rotate your body the opposite direction. When done correctly, the snap of the ankles will create force going forward and a extension of the leg. This extension will allow the body to naturally roll to the opposite side, to be done all over again.
Everyone is different, someone may be able to kick non stop while others just a couple kicks per stroke. Play around with these ideas and apply them to your own needs.
Until next time, stay wet!
(Want to learn more? Contact Jeremy Gregory