Every season there's a new way to go faster. A shoe, a powder, a protocol, a number your watch has suddenly decided you should care about. Some of it does something. A lot of it has never really been tested. So we go and find out, including the times the answer is boring.
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Video · 9:13
Explainer · 7 November 2026
Endurance starts to fade within about two weeks: the blood first, then the muscle, flattening out after two to three months. Strength from lifting usually lasts longer, bed rest and casts cost far more, and fewer but hard sessions kept most of it.
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Explainer · with videoIn the large trials, stretching did not prevent injuries.
Explainer · with videoNo trial has shown that thin shoes protect runners from injury.
Explainer · with videoThe longer you go, the more carbohydrate helps.
01▶ videoExplainerDetraining: how fast fitness fades when you stopThe blood goes first, the muscle next, and lying still costs the most.
02▶ videoExplainerStretching: what it does and doesn't do for runnersIn the large trials, stretching did not prevent injuries.
03▶ videoExplainerBarefoot and minimalist runningNo trial has shown that thin shoes protect runners from injury.
04▶ videoExplainerCarbs on the move: when, how much and which kindThe longer you go, the more carbohydrate helps.
05▶ videoExplainerFat, carbs and the fat-burning zoneYou burn both at every effort.
06▶ videoExplainerLab numbers, race numbersA study finds four per cent. What reaches the finish line is usually less.
07▶ videoExplainerTraining zones, from scratchZones are agreements about how hard you are going, not laws of nature.
08▶ videoExplainerWhat your watch actually measuresA sports watch senses about four things and works out the rest.
09▶ videoExplainerVO2max: what it tells you (and what it doesn't)The most-cited number in endurance sport, and what it can't tell you.
10▶ videoExplainerHow to read a training studySeven questions that tell you how far a finding travels.
11▶ videoCheck“Carbon-plate shoes make you 4% faster.”The famous 4% is now 2.75%, and most of it never reaches your finish time.
The six calculators, each showing its formula and where it stops being reliable: race pace · race-time predictor · heart-rate zones · climb times · aero watts · VO2max estimate.
Everything on this site is either something to read or something to use. The reading comes in two kinds — a promise put through the wringer, or an explainer that hands you the machinery underneath — and every piece says on the front which one it is. The rest is calculators you can run yourself. No training plans, nothing about your knee — we're not your coach and definitely not your doctor.
"4% faster." "8 watts." "Recovered by morning." We take these one by one, read what has actually been measured, and write down plainly what came out of it. Next to those, the explainers: VO2max, thresholds, fuelling, heat, why you slow down. Filter by sport, topic or kind.
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Pace converter, race predictor, heart-rate zones, climb times for the famous cols, an aero lab. Free, no login — and every tool says out loud where it bends, because that's kind of our whole thing.
Open the tools →
Carbon-plated shoes make you 4% faster.
It's done → read the full write-up: the numbers, the caveats, and who it is for.
Endurance media runs on gear. Test shoes that never go back, affiliate links, launch embargoes, a long weekend in Girona. It's not that those writers are liars — it's that you can never quite tell where the opinion ends and the arrangement begins.
So there's no arrangement. If a shoe is a marginal gain dressed up as a revolution, saying so costs us nothing.
One vote, no account — your browser just remembers you've voted. Whatever wins moves to the front of the queue; the full list lives on the library.
One thing at a time, dug into properly, reasoning out in the open. No schedule to keep up with, no filler. You can see what's in the queue right now.
No spam, we don't sell your address, and you can leave whenever you like.