It is fundamentally the most important thing you’ll learn…
Arms may be the accelerator, and breathing is crucial for staying down, but the legs are the consistency layer that brings it all together.
Why + Philosophy:
I always find myself telling my students “legs straight!”, as when they swim they are so focused on something else. Whether it be breathing, arms, or simply getting to the other side.
Yet the three simple steps are put in place for a reason, if you forget to kick then nothing else that you do matters. Only the arms will provide movement, and out of my years I’ve seen only a couple people out of a thousand swim with purely arms (disregarding using things like paddles). They were very upper body strong, but weak in the legs. It was out of balance
You need the basic movement speed from the kicks to keep you going, you can swim without arms believe it or not, but you can’t swim without legs.
How + Physics:
These are rough numbers, but I’d say that kicking provides about 60% of your movement. You only get the rest from the arms (maybe the push off wall). Meaning you can move with just your legs, and I often have students do such as that. By solely using the legs you can isolate your focus on the muscles there, work the lungs (as you can’t breath really without arms), and it shows you that you WILL move as long as you kick.
What is interesting to note too is that you don’t want to lock your knees, but try to keep them as straight as possible before that point. The pool itself will bend your knees ever so slightly, and it will flow with the waves.
What + Psychology:
It is weird when it comes to the brain, the only time I’ve seen people struggle mentally is when they were really young or really old. In both cases it was a neuromuscular connection thing, and over time would go away with practice.
It is a bit frustrating however when you tell your legs to move, and they aren’t doing exactly what you want them to. For example staying straight, and the knees want to bend when you apply the exertion in the kicks.
What is interesting is that the “kicking legs straight” actually applies to all kicks even. With frontcrawl you’ll be alternating leg kicking, but they are straight. With frog (breaststroke) kick, you are going out and bringing your legs back together. In the end of the kick they straighten back out. Finally, with the butterfly kick (dolphin) you are keeping your legs straight as before, but just simply kicking both legs at the same time.
This is just one example as to how the Three Steps to Swimming are for all strokes.
Always remember to kick straight AND consistently!
This is advice for people to level up their swimming, or perhaps get started in the first place. While you swim you should make sure you are doing so in a public facility with a lifeguard on duty for safety.