So as far as the propulsion is concerned – propulsion is another word that I use for speed. The reality is is that the propulsion generated from the Freestyle Kick isn’t actually that much. You get about 60 to 70% of the overall swimming Freestyle swimming speed from the arms and what the arms are doing, then you have 30 to 40% comes from the legs, so there is a pretty significant imbalance between what the arms and the legs are doing in Freestyle – this also equates to backstroke.
With that, though, it obviously still plays a vital role in speed generation like if you don’t kick it all you’re missing up to 40% of the speed that you could create, if you just drop the legs or you go into a 2-beat kick or something that is a little bit easier for you.
One of the other things it does is it helps keep the body moving forward through the breath. If you’re not kicking, your hands are creating very minimal propulsion, and you’ve changed a lot of things in your body line, so your body alignment if off too. Kicking through your breath make sure you are moving forward during those times, because that’s the goal with any stroke and swimming. It’s however much water you move backwards is how far you’re going to move forward and at the rate that you’re going to move forward at. So if you’re moving water pretty slowly, you’re not moving very much water behind you, you’re not going to move forward very much or very fast.
So, with propulsion, as well, it requires firing from all the muscles from the abdomen down – so as we talked about the Up-Kick versus the Down-Kick on what muscles are used in which are fired. You need basically all from your abs down to be working in order to generate speed from a Freestyle Kick.