Kick Efficiency Calculator
The formula
What the kick share tells you
The kick assessed two ways: its contribution to speed and its share of the metabolic bill, using heart rate above resting as the cost proxy.
Calculation: Kick share of speed; metabolic cost share from HR proxies. Enter your inputs and every substitution is shown below the result.
Reading the result
Distance swimming buys hip position from the kick; a kick that costs 80% of the cardiac budget at 2% of the speed is mispriced.
Rules of thumb: Kick-only ≈ 60–75% of free speed in trained swimmers
Limitations and best practice
HR proxies ignore stroke coordination and local leg fatigue — the fins-removed 400 tells the fuller story.
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
Does less kick make you faster?
Why is drag more than propulsion?
Source & methodology
Arellano kick-cost studies.
How Kick Efficiency works — and what your result really means
You are here because you need a specific number, and you want to see how it was produced before you rely on it. Kick Efficiency is the kind of number people argue about from memory. This page ends that argument with arithmetic you can watch happen: enter your figures, get Pull speed share in real time, and see every substitution printed below.
In Fitness & Sports the same quantity is often quoted under two or three different conventions. The formula printed above fixes one convention and applies it consistently, which is what makes results from this page comparable with each other.
Like most useful measures, Kick Efficiency 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.
Nothing below is stock text pasted around a number: the worked example computes pull speed share = 33.3 % from this tool’s own defaults, and the sensitivity section ranks the inputs that move the result — Full-stroke speed first, at ≈22.2 % of the headline for a ten-percent error either way in that input — which is the thread the rest of this guide pulls on.
Every input in Kick Efficiency, and what it does to the answer
Here is the complete model this tool runs — Kick share of speed; metabolic cost share from HR proxies — with each input explained below. If a competitor’s page gives you a different answer from the same inputs, this is the text that settles which of you is right.
Kick-only speed (m/s) (example value 1) is a measured number in the unit named by the label; the formula does not convert for you. This input feeds the formula directly; a defensible figure here is worth more than false precision anywhere else.
Full-stroke speed (m/s) (example value 1) is a quantity rather than a category — precision here is cheap and worth having. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
Heart rate kick-only (example value 145) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Rates are the most mis-transcribed input on any page like this; copy it from the document rather than retyping from memory.
Full-stroke HR (example value 165) is a numeric input whose unit is fixed by the label; a wrong unit is a wrong answer wearing a plausible disguise. Replace the example with the figure from your own records — the tool recomputes instantly and the printed steps follow your numbers.
Kick Efficiency on the example inputs: the complete substitution
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 speed (m/s), Full-stroke speed (m/s), Heart rate kick-only, Full-stroke HR. The endpoint of that chain is 33.3 % of pull speed share, sitting in the “Adding the pull to kick-only lifts speed by 33% — and the kick is eating 81% of the cardiac budget: a six-beat kick is luxury you are paying for” band.
- Share = (full − kick) ÷ full = 0.33
- HR proxy: (145−60) ÷ (165−60) = 0.81
- The kick sets body line; its propulsive share is secondary in distance swim
Kick-only vs full — 0.67 ratio. This is the number experienced users quote when the headline alone would mislead.
HR cost share — 81.0 %. Compare it against the main result of 33.3 % before drawing conclusions.
Beat recommendation — 2-beat or 4-beat for distance. Read next to the headline, this is the figure that shows the shape of the trade-off.
Snorkel test — kick-only with fins isolates the engine. Compare it against the main result of 33.3 % before drawing conclusions.
Keep this worked example open while you enter your own figures: matching the shape of the substitution is the fastest way to spot a unit or convention mistake.
Scenario table: Kick Efficiency at ±10 % and ±20 % of the key input
Read this table as the practical error bar on the headline figure. It answers the question people actually have after seeing a single number: how wrong could this be if the main input is off by ten or twenty percent?
| Full-stroke speed setting | Pull speed share |
|---|---|
| 80 % of the example value | 16.7 % |
| 90 % of the example value | 25.9 % |
| example inputs | 33.3 % |
| 110 % of the example value | 39.4 % |
| 120 % of the example value | 44.4 % |
That spread — 16.7 % at the low end, 44.4 % at the high — is what a careful read of Kick Efficiency looks like: a band you can state out loud, with the reason for each edge. Reproduce it in the form above by editing Full-stroke speed alone; the substitution steps will follow your figures exactly.
What actually moves your Kick Efficiency
Generic advice says “it depends on your inputs”; this section says exactly how much. Each field was perturbed by ±10 % in isolation and the pull speed share recomputed, so the ranking below is measured rather than asserted. It is the fastest honest answer to “what matters most in Kick Efficiency?” — and it is specific to these defaults, because sensitivity moves with the starting point.
- Nudge Full-stroke speed by ±10 % and Kick Efficiency lands between 25.9 % and 39.4 % (sensitivity ≈22.2 %)
- Kick-only speed +10 % → Kick Efficiency = 26.7 % · −10 % → 40.0 % (the pull speed share shifts ≈20.0 %)
Full-stroke speed is the dominant lever here: ten percent either way moves the result by about 22.2 %, from 25.9 % to 39.4 %. That is where a careless figure does the most damage, so check it against a source, and treat Kick-only speed as the second priority (≈20.0 % 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.
What a Kick Efficiency of 33.3 % means in practice
Nobody acts on a bare figure — they act on a figure with a comparison attached. The verdict attached to the default calculation — “Adding the pull to kick-only lifts speed by 33% — and the kick is eating 81% of the cardiac budget: a six-beat kick is luxury you are paying for” — is one band on a ladder your own figure may sit somewhere else on. The sensitivity list shows how far a modest input error moves you along that ladder: for Full-stroke speed, ±10 % covers 25.9 % to 39.4 %. The practical reading rules: ask what would have to change to move you one band. If the answer is “a small, plausible input difference”, the band itself is not the finding — the uncertainty is.
The comparison worth making is not with somebody else’s Kick Efficiency but with the version of your own situation measured last quarter — same formula, same conventions, different inputs.
Common mistakes with Kick Efficiency (and the fix)
HR proxies ignore stroke coordination and local leg fatigue — the fins-removed 400 tells the fuller story. 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 Efficiency can be dominated by one input whose absolute value looks unimpressive, which is why this page ranks influence separately from magnitude.
Attention is also misallocated between fields. Having measured this engine, we can say where it belongs: Full-stroke speed first, everything else second.
A final trap is presentation: reporting Kick Efficiency to more decimal places than the inputs support. The tool prints what the arithmetic gives; you should quote only what your least precise field justifies.
A quick check for any Kick Efficiency figure
- Note the date and the inputs beside the number so the figure can be audited later.
- Compare the result with one independent method or published benchmark.
- Check Full-stroke speed before anything else: it is the measured dominant input, ≈22.2 % of Kick Efficiency per ten percent.
- State, in one sentence, which convention each rate, unit or period in the form is using.
- Record the date and the inputs alongside the number so future-you knows what was assumed.
- Run the ±10 % stress on the top two levers and check that your conclusion survives both.
A routine for decision-grade Kick Efficiency
The tool does the arithmetic; the routine below is what makes the arithmetic trustworthy. Five steps, a minute total — and afterwards you will know not just what the number is, but which assumption produced it.
Step 1 — gather before you type. Kick Efficiency depends on kick-only speed (m/s), full-stroke speed (m/s), heart rate kick-only, full-stroke hr. 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. Comparisons are cheap: run the identical calculation for the alternative and look at the gap.
Step 2 — baseline before exploration. Get one defensible Pull speed share on screen before you start nudging numbers. Without a baseline, every variation looks interesting and none of them means anything. Rounding early is the quietest way to introduce a permanent error.
Step 3 — change one input at a time. Nudge a single field by ten percent, watch the headline and its companions move, then undo it. Two or three fields will dominate — the sensitivity table above already ranks them for this engine. If the answer changes your behaviour, it deserves a second run with different assumptions.
Step 4 — run the scenario trio. Expected, pessimistic, optimistic. The gap between pessimistic and expected is the number to plan against; the optimistic result is useful only as a ceiling. The inputs are the part of the work that nobody else can do for you.
Step 5 — schedule the next run. In Fitness & Sports the inputs drift quietly. Put a reminder a quarter out, re-enter the same fields, and read the change rather than the level. Compare the calculation to the rough guess you arrived with, and ask why they differ.
Where Kick Efficiency matters in practice
Fitness & Sports arguments end at arithmetic or they do not end. Kick Efficiency is the arithmetic: 33.3 % on the example inputs, reproducible by anyone who types the same numbers. Most surprises in numbers are surprises about inputs, not about formulas.
The companion outputs — Kick-only vs full and HR cost share — exist for the second stage of that screen: the headline sizes the prize, while the companions describe the trade-off you are accepting to get it. The fastest sanity test is to guess the answer first and see how far the calculation disagrees.
There is a personal-administration use people overlook: periodic self-checking. Kick Efficiency quietly drifts as life changes — rates move, bodies change, costs compound — and re-running it a few times a year catches drift while correction is still cheap. The fastest sanity test is to guess the answer first and see how far the calculation disagrees.
The questions that come up most about Kick Efficiency
What affects Kick Efficiency the most?
The short answer: Full-stroke speed. The longer answer is the sensitivity table on this page, where every numeric input was probed by ten percent and the pull speed share recalculated — Full-stroke speed moved it furthest, by roughly 22.2 % (25.9 % to 39.4 %).
Which matters more: kick-only speed or full-stroke speed?
For Kick Efficiency, Full-stroke speed wins the head-to-head (≈22.2 % against ≈20.0 % per ten-percent change). Knowing which input dominates is the difference between careful work and merely slow work.
What is a typical Kick Efficiency?
There is no honest universal average for Kick Efficiency, but there is a reference point: the defaults on this page produce 33.3 % (Adding the pull to kick-only lifts speed by 33% — and the kick is eating 81% of the cardiac budget: a six-beat kick is luxury you are paying for). Replace the inputs with your own and compare — that comparison is the useful meaning of “typical”.
How do I calculate Kick Efficiency by hand?
Kick share of speed; metabolic cost share from HR proxies is the entire method. Work the inputs in that order — Share = (full − kick) ÷ full = 0.33 — and you will reach 33.3 % on the default figures, the same number this tool prints.
What happens to Kick Efficiency if full-stroke speed changes by 10 %?
The engine was re-run with that field moved by ten percent while everything else stayed fixed: the pull speed share goes across 25.9 % to 39.4 %, a swing of roughly 22.2 % around the 33.3 % baseline. That ratio is the practical definition of how much this input matters.
Is the Kick Efficiency result of 33.3 % good or bad?
The tool answers “what”, not “whether”: 33.3 % carries the verdict “Adding the pull to kick-only lifts speed by 33% — and the kick is eating 81% of the cardiac budget: a six-beat kick is luxury you are paying for” for the default case, which is a starting interpretation rather than a verdict on your situation. Re-run with your own figures and compare the bands.
How do I calculate Kick Efficiency manually?
Write down the inputs, then follow the printed steps in order — Kick share of speed; metabolic cost share from HR proxies. A spreadsheet replicates it with two or three cells. The manual route is worth doing once to build intuition; after that the calculator saves time and eliminates transcription slips.
What affects Kick Efficiency the most?
Sensitivity depends on where you start, but the inputs Kick-only speed (m/s) and Full-stroke speed (m/s) typically move Kick Efficiency 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.
Does less kick make you faster?
For distance, often yes: dropping from six-beat to two-beat saves oxygen and keeps line.
Why is drag more than propulsion?
The legs sit low in the water column; their wake is the biggest passive drag source.
Can this tool see the numbers I type?
It cannot. There is no submission step: the calculation happens in your browser and the result disappears when you close the page. Treat the fields above as a scratchpad rather than a form.
The vocabulary of Kick Efficiency
- Kick-only vs full
- 0.67 ratio on the example inputs — a companion figure printed beside the headline of Kick Efficiency so that no result is read in isolation.
- HR cost share
- 81.0 % on the example inputs — a companion figure printed beside the headline of Kick Efficiency so that no result is read in isolation.
- Beat recommendation
- 2-beat or 4-beat for distance for the Kick Efficiency worked case; it sits next to the main result because it carries context the headline leaves out.
- Pull speed share
- The primary output of this tool: 33.3 % for the default inputs, computed exactly from Kick share of speed; metabolic cost share from HR proxies.
- Worked example
- The calculation written out in full so that nothing on this page has to be taken on trust.
- Verdict band
- The plain-language label — here “Adding the pull to kick-only lifts speed by 33% — and the kick is eating 81% of the cardiac budget: a six-beat kick is luxury you are paying for” — mapping the computed figure onto experience-based ranges for Fitness & Sports.
- Sensitivity (±10 %)
- How far the Kick Efficiency moves when a single input is nudged ten percent either way; the ranked list on this page is computed live from this engine.
Methodology, sources and limits
Everything above runs on one stated formula, applied without hidden coefficients: Kick share of speed; metabolic cost share from HR proxies. Source of record: Arellano kick-cost studies. 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. The sensitivity table above is part of that promise rather than a bonus: it lets you see how much of the result depends on how carefully you measured.
Turning this Kick Efficiency into a decision
Re-run the calculation with your own figures, stress the two most sensitive inputs by ±10 %, and only then act on the result.
The audience here is people who need one trustworthy number before their next decision. Everything you need to defend the result — formula, substitution, sensitivity, source — is printed above, so the only remaining variable is the honesty of your inputs.