Walk past any lap swim session and you see the same picture. A row of swimmers with their chins propped on a board, heads out of the water, chatting, legs thrashing behind them at an angle that would never appear in a race. Twenty minutes of that gets logged as kick work.
I swam the 200 individual medley at two Olympic Games for Brazil and won it at the 2015 Pan American Games in Toronto in 1:57.06, a race where the legs decide the last fifty, so I do care about kick sets. A board has one honest job, parking your hands so your legs cannot hide behind your arms. What it must not do is hold you in a position you will never use again once you let go. The board is not the problem. Where you hold it is.
Why does kicking with your head up drop your hips?
Because your hips go wherever your head sends them. US Masters Swimming puts it in five words in its guide on how and when to use a kickboard: "when your head is up, your hips are down."
The appeal is obvious and the guide admits it, since "if you're riding the board with your hands grabbing it out front and your head up, you can see and breathe." It also names the cost, which is not only your hips, because that position "can also cause you to strain your neck."
The other US Masters article, Time to Ditch the Kickboard, states the rule underneath all of it: "Remember, your spine must be aligned from the base of your skull to your pelvis." Lift your head and that line breaks at the neck, the pelvis tips, and the legs sink. Same mechanism as in why your legs sink when swimming and head position in freestyle, except now foam is holding you in the fault for the whole set.
It also names a consequence I see constantly: "kicking with your head up can cause you to develop an asymmetrical kick." One leg works harder than the other because the hips are no longer square. You are not training your kick. You are training a limp.
How should you hold the board in freestyle?
By the back edge, with your face in the water. The kickboard guide is direct: "For freestyle, it's better to grab the back of the board and put your face in the water."
The reason matters for freestyle in particular. Holding it that way "keeps a more natural alignment for your body and allows you to gently rotate." Freestyle turns around its long axis. Clamp your chest onto a flat board and you lock the hips square, which removes what the freestyle kick has to coordinate with. Grip the far edge and your shoulders stay free to roll.
Face down raises the breathing question, and the guide answers it plainly: "Using a snorkel is best." The other article agrees, saying a snorkel "makes kick sets much more efficient, as you won't need to lift your head to breathe." Without one, breathe by rolling to the side rather than lifting your chin forward. Forward is what costs you your hips.
Is a kickboard better in breaststroke and butterfly?
Yes, and the reason is anatomical. The guide explains that "It's much easier to isolate your kick with a kickboard in the short-axis strokes" because in those strokes "the hips stay flat." The board is not fighting the stroke the way it fights freestyle.
The grip rule does not change, though. "If you lay your forearms across the board and grab the front of it, your hips and legs will sink," the guide warns, with the same fix of grabbing the back of the board and putting your face in the water. In breaststroke that position lets you feel whether you are bringing your heels to your hips instead of your knees to your chest.
Should you use a board at all, or kick in streamline?
Kick in streamline for most of your kicking and keep the board for drills. Time to Ditch the Kickboard opens with the question that settles it: "We don't swim with our heads up, so why kick that way?"
On head-up flutter kicking it does not hedge: "You shouldn't ever, actually, unless you're doing a drill or playing water polo." Its standard for any kick set is the line to remember: "make sure you're doing it in a position that best mimics your swimming position."
Streamline kicking does that. Hands stacked overhead, head between the arms, body on one line, the position you leave every wall in and the one I broke down in streamline and push-off from the wall. One warning applies there too: "If you submerge too far, your head will point the rest of your body toward the bottom of the pool."
The same article flags that a head-up kick "can cause a great deal of tension in your lower back, upper back, and neck." If your lower back aches after kick sets, that is your answer, not a sign that you need a stronger core.
How does SwimRead read this part of your swimming?
It reads your legs inside your actual stroke, not inside a kick set. The SwimRead home page states that "The current beta supports freestyle filmed from the side of the pool," and that "Backstroke, breaststroke, butterfly, underwater footage, starts, and turns are not supported analysis modes in this beta."
So the clip to film is the swim. The page asks you to "Aim for 10 seconds of continuous freestyle," filmed "in landscape from the side, with the whole body visible, a stable camera, standard lens, and normal playback speed." From that footage, "On-device pose detection estimates up to 33 body landmarks in sampled video frames," and "The app does not upload your video."
It will not hand you a verdict. Asked whether it gives technique a score, the page answers "No," and states that "These estimates are not validated technique grades." What a side-on clip does show is head and body line, which is what a head-up board habit quietly ruins.
What should you drill this week?
- Board flat, head down. From the US Masters kick drills page: "Hands on the end of the kickboard, arms fully extended and kickboard flat on the water." Then "Head should be down between the arms, ears even with the arms and gentle flutter kick."
- One hand in, one hand out. Same page: "Repeat the same drill but one hand moves to the middle of the board, the other remains at the side," with "Heads down (ears at arms) and focus is on gentle rotation to breathe." This is the freestyle version, because it lets the roll happen.
- Tombstone. "Swimmers hold the kickboard out fully upright in front to look like a tombstone and start kicking," and "The goal is to keep only the minimal amount of the kickboard in the water." It exposes a weak kick in fifteen seconds.
- Streamline kick. No board. Hands overhead, head between the arms, and compare the time to your board repeats over the same distance.
Time those repeats and run them through my free swim pace calculator to see whether the position change bought speed or only felt harder.
SwimRead is free while in beta, and paid plans will come later, with beta testers told before anything changes. If you want a reading of your freestyle body line from the side, join the beta and leave your email for an invitation as beta spots open.