At my last workshop in Kazan Russia a student (a swim instructor taking our course for the first time), after listening to our ideas about training, asked, “But what about kickboards then? Do you use them?”
I paused, looked at her, and asked in return, “And what skill are you intending to build with a kickboard? There is no kickboard event in the Olympics.”
See, every movement of muscle is building a skill- a pattern of control. You cannot simply exercise muscles without also building and reinforcing the neuro-muscular controls surrounding that movement. Muscles are simple- the signals you send turn them on, or off. The signals you send travel through the brain, and down the nervous system on a certain pathway to get there. The more often that signal is sent along that pathway the stronger that pathway becomes and the harder it is to fire those muscle combinations in a way different than how you’ve been exercising them.
So in the case of doing kickboard sets, you are building really good control over kicking in that exact position. However, kicking while also performing the freestyle (crawl) stroke has your body in a different position- or rather, a dynamic pattern moving from position to position. Only a fraction of the crawl stroke is in the flat position, while an entire kickset is done flat. None of it has a back that is arched and the head up, out of the water. Kicking with a board also reinforces the separation of the “leg-motor” from the “arm-motor”- a disconnect between the front half of the body and the back half. Although the technique intends to create more combined power by the two engine approach, the disconnect at the waist causes the energy flowing through the body to conflict and work against much of itself, rather than work in a whole, synchronized power-directing unit.
This two-motor swimming technique produces a lot of waves, splash, bubbles, and noise- the things traditional swimming has falsely come to associate with power and productivity in the water. Physics tells us a different story: waves, splash, bubbles, and noise are the evidence of wasted energy in water. Ask any naval engineer.
So my recommendations for using a kickboard? If you must use one, then learn to kick as quietly as possible. Keep the feet underwater, try to make no bubbles while kicking.
But better yet, if you insist on kicking without synchronizing with whole body rotation, do away with the kickboard, and at least kick in the prone position that you would while using the crawl stroke. For this, the Finis Snorkel is a great device- it allows you to keep you head down and spine aligned (only if you look down, not forward). [Note: if you have great balance, especially with head-down alignment, you’ll notice how the air in the snorkel will push up against your head, causing a little tension in the neck- no fault of the Finis Snorkel- just a fact of physics, pushing air down into the water will cause the water to push it back up.]
Better yet, learn to perform a 2-Beat Kick (one kick for each stroke- the left foot flicks down at the moment the right hand is spearing into the water in front, for example) where you draw your power from the core rotation- the foot presses against the water allowing you to turn the torso and drive your energy forward through the spearing front hand- like you would take a golf swing, or tennis swing, or karate punch.
A 2-Beat Kick will require you to fine tune your whole leg movement, from hip to toe in the most effective motion. By stripping the kick down to this elemental rhythm you’ll discover that the best part of the kick happens at the flick from the ankle to the toe, and in the precise forming and timing of that moment. It will connect your whole body from toe to finger tip in a synchronized rhythm that allows you to generate fare more power with far less effort than a two-motor body can. You can argue with me all you want about this, but don’t bother until you perfect the 2-Beat and see for youself. You can check out Sun Yang swim his world-record 1500 meter swims using it for 14 of 15 consecutive 100’s at 58 seconds per 100. I know people can kick fast with a 6-beat, but it does not tell us everything about how skillful they are as a kicker and how well energy is being managed.
We can apply this argument to pull-buoys also. Those are a device that may have some isolated benefits but for the most part they interrupt a swimmer’s need to develop and strengthen full-body balance. I rarely see them in a way that might help isolate and train the superior back muscles. Without careful instruction they make it way to easy to train people to swim from the shoulders instead of the core. I ditto this for hand-paddles as well. Both useful devices if used with extreme care and attention to exactly what skill is being developed. Yet I contend that these devices are traditionally (intentionally or ignorantly) used to build inferior skill sets, when they could be put to better use.
The general principle here is this: when you exercise muscles you are building skill. Decide what skill you want to build then work on that- the muscles will form and strengthen according to the specific skill you seek. Be very careful about exercising muscles in isolation and in patterns (e.g. dry-land training, free weights, bands, boards, gadgets, medicine balls, etc) that do not closely match the actual activity they will be used for. During our activity, like in swimming, muscles do not work independently- but in a complex arrangement of intensity, sequence and timing- you can easily create an imbalanace in a joint or in a movement pattern with isolated exercises that do not work the entire joint together in the 3-dimensional pattern it will work in during the actual stroke.
Also, great skill does not magically appear just because someone has toned their muscles really well. A person can develop a great deal of speed in a kick from kickboard sets but do so at a great waste of energy- even in the kick, technique is everything, muscle power is subordinate to that.