If there is one thing that is often overlooked by swimmers, it is most definitely the kick. Being a distance freestyler most of my life, I never felt the need to use my legs during a race. The kick is not only a large part of forward propulsion, but it assists in proper body position and promotes strong rotation in free and back. Before diving in completely, I should clarify the focus of this article is on the freestyle, backstroke and butterfly kick – breaststroke kick and underwater streamline kicking is an entirely separate topic.
Freestyle and backstroke kicking is almost identical but the main difference is body position in the water. Keep in mind that when you are doing these strokes, the majority of the stroke is most efficient on your side. The less ‘flat’ you are in the water, the better. As a result, the majority of your kick should be sideways or at least at an angle. A great way to think about this is the way fish are designed. Fish don’t swim up and down, they swim side to side. Why is that? Simply, because it is faster.
Let’s start with freestyle. Facing down and rotating from side to side, a good body position would have the head, hips, legs, and feet right at the surface of the water. We know that when you kick, you move the water and propel your body forward. Your legs are also extremely important for keeping that good body position. Kicking helps you to keep your body position higher in the water as opposed to sinking. When you drive with your legs, not only do your hips stay up in the water but it naturally forces your head down. This creates an ideal “downhill” swimming position to maximize your forward propulsion. Kicking also helps body rotation. The rotation and speed of freestyle is derived from the rotation of the hips – it’s how the stroke works. A strong kick actually helps to drive hip rotation and speed it up, making for a faster and generally better stroke.
As previously mentioned, backstroke kicks work is almost identical to freestyle. The ideal body position is the same as freestyle: everything should be around the surface of the water. The head position is important because it needs to stay in the water, but the chin needs to remain tucked so you are looking straight up. The drive from your kick actually makes this very easy. My club coach in middle school once told me to imagine that every time I kick upward on backstroke, I am kicking a beach ball up in the air. It is essential for the feet to break the surface, as well as come back down underneath the water surface. Backstroke rotation is even more critical because of the entry of the stroke. Without rotation there is no stroke, and a solid kick helps that rotation back and forth. If you swam backstroke without rotation, it would not only be difficult and slow, but you would most likely hurt your shoulders from stress on the joints. Whether it is freestyle or backstroke, kicking is necessary for success in the strokes.
Butterfly is a bit different than free and back with the most obvious change being that there is no rotation. The stroke is powered from two things: the hip motions and the kick. There is sort of a pattern in swimming that the hips and the legs are important. In fact, butterfly kick is like a process. The hips help push your chest down on the stroke. The down kick helps push the hips up. Every facet works within each other. In the mechanics of the butterfly kick, we remember that there are two kicks in each butterfly stroke. The first kick should be a small propulsion that occurs underwater. This happens during the beginning of the stroke. The second is the “thump” kick, which should make a splash. This should be during the recovery of the stroke when the hands are surfacing. This not only throws you forward, but it pushes the hips up and throws the hands back down to complete the recovery. Butterfly is not as much of a muscle stroke as many make it out to be. The better you are at kicking and using your hips, the easier the fly becomes. Remember it will always be in the hips and there are no hips without the kick.
Now let’s return to the three strokes and look at the kick in a different light. When you kick, you don’t kick in one direction, you kick up and down, down and up. With fly, it is important to get your feet up to thrust them down. A former Cal Berkeley coach once explained to me that on the thump kick on fly, you want to focus on going up with your feet. It took a while for this to make sense. I believe it works to focus on the down or the up, but the big point is that it is important to have thrust going both up and down with your feet. Both are effective, and the human foot is shaped to be propulsive on the top and bottom.
With free and back, the idea of having propulsion in both directions is more obvious because your feet should be going in opposite directions. Remember to break the surface of the water while getting your feet back down below. And again, just like with butterfly, the recover position of the feet is important to keep the hips up and rotate from side to side. Scientifically, the body is designed to be able to kick both directions. The up and down kick engage different muscle groups. The legs are the strongest part of the body. They also coincidentally give the body the best workout. Coaches agree that kicking needs to be done every day in practice to make a complete swimmer. So get those legs moving because you will definitely feel the difference.