Kick Board Effort Calculator
The formula
What the kick exchange rate tells you
What the board session is really telling you: how much of free-swim speed the legs alone produce, and what cardiac price is paid for it.
Calculation: Kick speed ÷ free speed = propulsion share; HR %max = cost. Enter your inputs and every substitution is shown below the result.
Reading the result
Speed share of 65 %+ at under 85 % HR is a gift; 55 % at 92 % HR says the kick is an anchor and the season needs kick technique, not more kick sets.
Rules of thumb: Club kick-only ≈ 60–75 % of free speed; elite two-beat distance kick ≈ 70 %
Limitations and best practice
Gripping the board high lifts the hips artificially — compare only board-to-board, never to a stream-line kick test.
This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Frequently asked questions
Why does kick HR spike so fast?
Does a bigger board help?
Source & methodology
Boniymol/Cappaert kick analyses; club testing.
How Kick Board Effort works — and what your result really means
This page was written for one job: turning your own inputs into a defensible figure, with the working shown. There are plenty of pages about Kick Board Effort; almost none of them show the working. This one does: the formula, every input, a fully computed example, and a sensitivity analysis calculated live from this engine’s own defaults.
There is a habit that separates people who get useful answers from Swimming numbers: they decide what question the figure answers before they compute it. Kick Board Effort answers “Kick speed share?” — and nothing else, which is precisely why the result is trustworthy.
Like most useful measures, Kick Board Effort is a summary, and summaries hide as much as they reveal. The companion outputs and the input table are here to reopen what the headline compressed.
Every figure in the prose is generated by the engine rather than written beside it — the worked example resolves to kick speed share = 63.3 % on the default inputs, and the sensitivity section ranks the inputs that move the result — Kick-only 25 m first, at ≈11.1 % of the headline for a ten-percent error either way in that input. Work down the page and by the end you could re-derive the result in a spreadsheet from memory.
The Kick Board Effort formula, explained
One formula, published in full: Kick speed ÷ free speed = propulsion share; HR %max = cost. Anything you can read, you can reproduce in a spreadsheet, and that reproducibility is the whole point of printing it rather than hiding it behind a button.
Kick-only 25 m (s) (example value 30) is a plain measured quantity — the unit shown in the label is the unit the formula expects. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
CSS pace /100 (s) (example value 76) is a measured number in the unit named by the label; the formula does not convert for you. The example value is there to demonstrate the mechanics, not to describe your situation — overwrite it.
Kick heart rate (bpm) (example value 161) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Enter it exactly as your document states it — quoted annual, monthly and effective rates are three different numbers.
Max HR (bpm) (example value 188) is a quantity rather than a category — precision here is cheap and worth having. If you are unsure what belongs in this field, look at the printed steps: the substitution shows exactly how the engine uses it.
The default Kick Board Effort calculation, written out in full
The tool prints its own working; this is the same arithmetic on the example values, reproduced so you can follow it by hand. Starting figures: Kick-only 25 m (s), CSS pace /100 (s), Kick heart rate (bpm), Max HR (bpm). The endpoint of that chain is 63.3 % of kick speed share, sitting in the “The board kick carries 63 % of free-swim speed at 86 % of max heart rate — a reasonably priced kick — trained swimmers sit at 60–75 % speed share” band.
- Kick = 25 ÷ 30.0 = 0.83 m/s
- Free = 100 ÷ 76.0 = 1.32 m/s
- Share = 63.3 % at 85.6 % HR
Kick speed — 0.83 m/s. Compare it against the main result of 63.3 % before drawing conclusions.
Free speed — 1.32 m/s. Compare it against the main result of 63.3 % before drawing conclusions.
HR cost — 85.6%. This is the number experienced users quote when the headline alone would mislead.
Cost-to-speed gap — 22.3 pts. Compare it against the main result of 63.3 % before drawing conclusions.
Overwrite any input above and every line of this example updates with it — the substitution is live, not a screenshot of somebody else’s numbers.
Scenario table: Kick Board Effort at ±10 % and ±20 % of the key input
Single-point answers invite false confidence, so the same engine was run across a band around the input that matters most here. Each row is a full recalculation of Kick Board Effort, not an interpolation.
| Kick-only 25 m setting | Kick speed share |
|---|---|
| 80 % of the example value | 79.2 % |
| 90 % of the example value | 70.4 % |
| example inputs | 63.3 % |
| 110 % of the example value | 57.6 % |
| 120 % of the example value | 52.8 % |
That spread — 52.8 % at the low end, 79.2 % at the high — is what a careful read of Kick Board Effort looks like: a band you can state out loud, with the reason for each edge. Reproduce it in the form above by editing Kick-only 25 m alone; the substitution steps will follow your figures exactly.
Where Kick Board Effort is fragile — and where it is not
Nobody should have to guess which input matters. The engine was re-run once per field below — ten percent up, ten percent down, everything else frozen — and the results ranked by how far they moved the kick speed share. It is the fastest honest answer to “what matters most in Kick Board Effort?” — and it is specific to these defaults, because sensitivity moves with the starting point.
- Nudge Kick-only 25 m by ±10 % and Kick Board Effort lands between 57.6 % and 70.4 % (sensitivity ≈11.1 %)
- Nudge CSS pace /100 by ±10 % and Kick Board Effort lands between 57.0 % and 69.7 % (sensitivity ≈10.0 %)
Kick-only 25 m is the dominant lever here: ten percent either way moves the result by about 11.1 %, from 57.6 % to 70.4 %. That is where a careless figure does the most damage, so check it against a source, and treat CSS pace /100 as the second priority (≈10.0 % per ten percent). The rest of the inputs earn only a rounding-error of attention, and that asymmetry is the practical payoff of measuring rather than asserting.
Is your Kick Board Effort good — reading the result bands
The value above only becomes useful the moment you know what it is being measured against. On the example inputs the band reads “The board kick carries 63 % of free-swim speed at 86 % of max heart rate — a reasonably priced kick — trained swimmers sit at 60–75 % speed share”; your own figures place you on a different rung of the same ladder. Before treating the band as fact, note its width: ten percent either way on Kick-only 25 m already spans 57.6 % to 70.4 %. The practical reading rules: read the band as a starting hypothesis, then test it: change the two dominant inputs by ten percent and see whether the verdict survives. Verdicts that survive stress are the ones worth acting on.
Where Kick Board Effort sits next to similar measures: this tool answers “how much is the Kick Board Effort”, while the related calculators answer “what do I do about it”. Reading the result alone tends to over-weight a single snapshot; pairing it with the companion tools above turns the number into a decision.
Common mistakes with Kick Board Effort (and the fix)
Gripping the board high lifts the hips artificially — compare only board-to-board, never to a stream-line kick test. This calculator gives an estimate based on standard formulas; it is not professional financial, medical, legal or engineering advice. Verify anything you plan to act on with a qualified professional and your own records.
Confusing a large number with an important one. Kick Board Effort can be dominated by one input whose absolute value looks unimpressive, which is why this page ranks influence separately from magnitude.
This model has its own particular trap: Kick-only 25 m carries ≈11.1 % of the response per ten percent of error, so effort spent elsewhere is largely decorative.
The subtlest error is answering the wrong question precisely. Confirm that kick speed share is actually the quantity your decision needs — the arithmetic is flawless either way, which is what makes the mistake invisible.
A quick check for any Kick Board Effort figure
- Compare the output against one published benchmark or a colleague’s independent estimate.
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Put Kick-only 25 m under a magnifier; the sensitivity table above is the reason why.
- Check that every field the formula needs actually arrived from a document, not from recollection.
- Confirm the example values are plausible for your own situation before replacing them.
- Run the ±10 % stress on the top two levers and check that your conclusion survives both.
A routine for decision-grade Kick Board Effort
Using a calculator well sounds trivial, but the difference between a decision-grade figure and a throwaway one lives entirely in the routine. The routine for Kick Board Effort takes a minute to learn and applies to every input above.
Step 1 — gather before you type. Kick Board Effort depends on kick-only 25 m (s), css pace /100 (s), kick heart rate (bpm), max hr (bpm). Collect them from a source document — a statement, a report, an invoice, a log — rather than from memory, because recalled inputs are the single largest cause of wrong results. Estimates improve most when the worst case is written down in ink.
Step 2 — start from the case you can defend. Enter pessimistic-but-honest figures first; the optimistic run is a ceiling, not a plan. A conclusion that holds on conservative inputs holds everywhere. A calculation you cannot explain to somebody else is a calculation you cannot defend.
Step 3 — isolate your variables. Change one field, observe, revert. The live sensitivity list does the ranking for the default inputs; verify it against your own, because dominance shifts when the starting point shifts. If the answer changes your behaviour, it deserves a second run with different assumptions.
Step 4 — compute a corridor, not a point. Three runs — worst, likely, best — turn Kick Board Effort from a snapshot into a range. Plan against the pessimistic end and treat the optimistic end as the upside story. Numbers are cheap to produce and expensive to retract; the extra minute is the cheapest insurance available.
Step 5 — record the context, not just the number. Note today’s date and the inputs alongside the 63.3 % output. Six months from now the context is what turns this figure into a trend. Write the figure down before moving on; memory flatters whichever number you saw last.
Where Kick Board Effort matters in practice
Most Swimming disagreements are arithmetic disagreements in disguise. When Kick speed share of 63.3 % sits on the table with its working shown, the conversation stops being about who sounds more confident and starts being about which input is wrong. Re-running a number costs seconds; retracting a decision costs considerably more.
Used properly this is a five-minute filter that saves weeks. Compute Kick Board Effort, reject what fails, and only then bring in the expensive analysis for the survivors. Write the figure down before moving on; memory flatters whichever number you saw last.
Nothing here is stored or transmitted, so the habit of checking is free: open the page, re-enter current figures, compare with the number you saved last time. Note the assumption you are least sure about; that is where the real risk lives.
The questions that come up most about Kick Board Effort
What affects Kick Board Effort the most?
Measured on this engine, Kick-only 25 m is the dominant lever: moving it ±10 % shifts the kick speed share across 57.6 % to 70.4 % — about 11.1 % of the headline, with CSS pace /100 next at ≈10.0 %. The ranked list in the sensitivity section is computed live, not asserted from a template.
Which matters more: css pace /100 or kick-only 25 m?
Kick-only 25 m, by a factor of about 1.1. Concretely: ten percent on Kick-only 25 m is worth ≈11.1 % of Kick Board Effort, the same nudge on CSS pace /100 only ≈10.0 %. That ranking is re-computed for each page from that page’s own defaults.
What is a typical Kick Board Effort?
There is no honest universal average for Kick Board Effort, but there is a reference point: the defaults on this page produce 63.3 % (The board kick carries 63 % of free-swim speed at 86 % of max heart rate — a reasonably priced kick — trained swimmers sit at 60–75 % speed share). Replace the inputs with your own and compare — that comparison is the useful meaning of “typical”.
How do I calculate Kick Board Effort by hand?
Use the stated model — Kick speed ÷ free speed = propulsion share; HR %max = cost — and substitute in the order the tool prints (it starts from Kick = 25 ÷ 30.0 = 0.83 m/s). On the example inputs the hand route lands on 63.3 %, exactly what the calculator shows. A spreadsheet reproduces it in two or three cells; doing it once by hand is what makes the automated answer trustworthy.
What happens to Kick Board Effort if kick-only 25 m changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the kick speed share goes across 57.6 % to 70.4 %, a swing of roughly 11.1 % around the 63.3 % baseline. That ratio is the practical definition of how much this input matters.
Is the Kick Board Effort result of 63.3 % good or bad?
Good and bad are comparisons, so the honest test is three questions: where does your own Kick Board Effort sit against the 63.3 % reference above, how far would a plausible input error move it (≈11.1 % per ten percent on Kick-only 25 m), and what does the alternative option compute to?
What affects Kick Board Effort the most?
Sensitivity depends on where you start, but the inputs Kick-only 25 m (s) and CSS pace /100 (s) typically move Kick Board Effort further than the rest because they enter the formula multiplicatively. If you can only measure two things well, measure those and hold the others at conservative defaults.
How often do I recheck Kick Board Effort?
Whenever Kick-only 25 m (s) changes materially, or on a deliberate block cycle (4–8 weeks is standard practice). A stale Kick Board Effort under-programs strong athletes and over-programs tired ones.
Why does kick HR spike so fast?
Working muscle mass with poor venous return in a horizontal, iso-metric hold — local fatigue drives the cardiac drift.
Does a bigger board help?
It changes hip position; use one board consistently, or the trend line means nothing.
Do I need an account to use this Kick Board Effort calculator?
No, and no data leaves the tab. The engine runs in the page itself, which is why the worked example, the bands and the sensitivity ranking all respond instantly to your keystrokes.
What the labels on this page mean
- Kick speed
- 0.83 m/s for the Kick Board Effort worked case; it sits next to the main result because it carries context the headline leaves out.
- Free speed
- 1.32 m/s for the Kick Board Effort worked case; it sits next to the main result because it carries context the headline leaves out.
- HR cost
- 85.6% in the default Kick Board Effort calculation — one of the secondary figures an experienced reader checks before trusting the primary number.
- Kick speed share
- The primary output of this tool: 63.3 % for the default inputs, computed exactly from Kick speed ÷ free speed = propulsion share; HR %max = cost.
- Worked example
- The step-by-step substitution printed above, so the arithmetic can be re-derived by hand or in a spreadsheet.
- Verdict band
- The plain-language label — here “The board kick carries 63 % of free-swim speed at 86 % of max heart rate — a reasonably priced kick — trained swimmers sit at 60–75 % speed share” — mapping the computed figure onto experience-based ranges for Fitness & Sports.
- Sensitivity (±10 %)
- How far the Kick Board Effort moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
The provenance of this Kick Board Effort calculation
The model is published arithmetic implemented exactly as written: Kick speed ÷ free speed = propulsion share; HR %max = cost. Source of record: Boniymol/Cappaert kick analyses; club testing. Any other implementation of this model should return the same figure for the same inputs. If one does not, the difference is in its assumptions — which this page prints and that one probably does not.
Treat the output as a precise answer to the question you typed: exact arithmetic, transparent formula, published source, no hidden rounding. What that buys you is reproducibility — two people, two browsers, the same arithmetic, and a printed trail from inputs to result that either of them can audit.
What to do with your Kick Board Effort next
Save the number together with its inputs and today’s date; a Kick Board Effort figure without context is unusable the moment an input changes.
This page was written for people who need one trustworthy number before their next decision, and the promise is that nothing above required trust. Bookmark the tool, re-run it whenever an input moves by more than a few percent, and keep the date with the number.