Long-form writing about training, racing, equipment and the physics of virtual cycling. Every article is written and maintained by Christian Lassen Dam, carries a publication date, and links to the sources behind any number it quotes.
This library grew out of a single question: how long will this climb take me? Answering it properly meant working out what actually governs speed on a gradient, and that pulled in everything else - how power is measured, why indoor numbers differ from outdoor ones, how drafting works when there is no air, and why the same rider can produce two very different times on the same climb a week apart.
If you are new here, the fastest route into the site is to run a number through the Alpe du Zwift calculator and then read the pacing guide for that climb. If you would rather understand the machinery first, start with power-to-weight ratio and then how the calculators were fitted.
Articles are grouped into four hubs. Each hub page is a guide in its own right, not just a list of links - it explains how to think about that part of the sport before pointing you at the detail.
The articles and the calculators are meant to be used together. An estimate without context is a number you cannot act on, and a training article without a number to aim at is hard to apply.
Your power is not the same at 6 AM as at 6 PM, but nobody can tell you how large your own swing is. What actually moves across the day, why it moves, and a six-session protocol that measures the effect on you rather than on a study population.
The places you lose in the last ten minutes are rarely a fitness problem. Which parts of the screen are worth watching, why judgement degrades as the effort rises, and how to strip the load out of a race before it starts.
The subscription is rarely the expensive part. A break-even formula you can run on your own ride count, the full cost stack including the trainer, and an honest account of when Zwift is not worth paying for.
Outdoors you shift position constantly without noticing. Indoors the bike cannot move, so you stop moving too. What that does to your hands, knees, neck and lower back over a winter, and the changes that actually help.
Zwift sends far less data than people assume, so raw latency is almost never the culprit. The failure modes in order of how often they actually happen, a diagnostic sequence you can run tonight, and what a bad connection cannot be blamed for.
Drafting saves air resistance, and air resistance depends on speed, so the draft is worth a great deal on the flat and close to nothing on the Alpe. Where the crossover sits, how to measure your own saving, and which numbers people invent because Zwift has never published them.
A flat route and a climb turn identical watts into completely different sessions. Why gradient rather than scenery decides what a ride trains, the three ways route choice quietly wrecks a training block, and how I lay out a week.
Company raises your output and also makes it easier to hide. Why large groups feel easy, what a ride leader actually controls, why group power averages mislead, and how to get a real session out of a social ride.
In Zwift a bike is three numbers rather than a machine, and the fastest one up the Alpe is not the fastest one on the flat. A decision table for choosing a setup, and the reason equipment is the least efficient place to look for speed.
Riding hard every week stops working after about two months. The three time scales a plan has to handle, a worked sixteen-week structure, how to plan backwards from a climb attempt, and why a permanent sweet spot block is the most common way to stall.
About 800 verified ZwiftPower finishing times, fitted to two curves, and nothing else. What those equations really say about the value of a power gain, how to read a target time backwards into a wattage, and exactly where the model stops being trustworthy.
Every watt you make crosses six or seven interfaces before it becomes speed on screen, and each one takes a cut. Torque and cadence, drivetrain losses, in-game mass, and why a quadratic curve fits climbing times better than a straight line.
Where roughly 800 ZwiftPower records came from, which curve shapes were tried and rejected, how each fit was checked against data it had never seen, and the ranges outside which these models should not be trusted.
Watts per kilogram predicts climbing speed because on a steep gradient nearly all your power goes into lifting your own mass. Where that stops being true, the two ways to move the ratio and why they are not equal, and the point at which chasing it backfires.
How a gamer on a borrowed trainer ended up training for an Ironman, what a YouTube series had to do with it, what the numbers and the weight actually did over that first year, and the things I would do differently starting again.
What ends streaks on the road is decision fatigue, not missing equipment. A minimum ride small enough to defend on any day, three travel scenarios from full kit to no bike at all, and the rules that stop the streak becoming a burden.
Written from the middle of an engineering degree. The minimum weekly dose that still builds fitness, where student time actually disappears, how to train through an exam period without sabotaging either one, and a three-ride template that survives a chaotic week.
FTP, w/kg, ERG, the blob, sticky draft, sandbagging, the pen. What each term means, which ones a beginner needs first, and the handful that get used incorrectly in ride chat often enough to be worth correcting.
Indoor sweat lands where rain never reaches and it is saltier than rain too. What corrodes first, why one towel is not enough, the three-minute routine after a ride that prevents nearly all of it, and the early warning signs.
Seven days is an arbitrary container for training, and it forces hard sessions closer together than they need to be. A ten-day rotation that gives threshold, VO2, endurance and running room to breathe, with the intensity guide that keeps it honest.
Zwift is very good at building an engine and completely unable to teach you to descend, corner or read traffic. An honest split of the two lists, and how to cover the gap without giving up what indoor training is genuinely good at.
A Zwift climb punishes a pacing error within a minute. A headwind punishes your mood for three hours. Why the two kinds of difficulty are not really comparable, which one prepares you better for a long day outdoors, and how to use both.
A long, flat, stop-often day on the bike asks for durability and patience, not threshold power, and most riders train for the wrong one. Using Japan's Shimanami Kaido as the example: what the day demands, the Zwift block that builds it, and why the week afterwards matters more than the week before.
Gravel is not simply road riding that is harder. It changes the shape of the effort, and that changes the sessions that prepare you for it. What each surface asks of you, and how to reproduce both on Zwift when the roads outside are not available.
Altitude takes power away before you turn a pedal, and no amount of indoor training gives it back. What thin air actually costs, why your heart rate stops meaning what it used to, and how to build the one thing that does transfer: the ability to ride steadily for a very long time.
Zwift's New York is a park loop with future architecture bolted on, and it rides nothing like the real thing. What the in-game routes actually train, how the real city differs, and how to use the world for the punchy, stop-start efforts urban riding demands.
The jump from a two-hour ride to a five-hour one is a fuelling and pacing problem far more than a fitness one. What changes past the three-hour mark, the Zwift progression that gets you ready, and the mistakes that turn a good day into a long walk.
Riding well on day three is a different skill from riding well on day one, and single hard sessions do not build it. How consecutive-day fatigue actually accumulates, the Zwift block that prepares for it, and how to pace a tour so the last day is still enjoyable.
Drag rises with the cube of speed, most of what you produce leaves your body as heat rather than motion, and the flywheel is not storing what you think it is. An essay on the physics that decides how fast a given number of watts makes you go.
Sports nutrition is mostly sugar sold at a considerable markup. What is actually inside a gel, how table sugar and maltodextrin reproduce it for a fraction of the price, why the wrapper does more work than the contents, and how much sodium you genuinely need.
An essay rather than a guide. Watopia as a place with its own physics, its own etiquette and its own quiet class system, written from several thousand kilometres spent inside it.
The central governor, the Proteus effect, and the reason a progress bar changes what your legs will agree to. Why the same effort is easier to tolerate with a screen in front of it, and the point where that stops being useful to you.
The Alpe is 21 hairpins and the gradient changes on every one of them. A pacing script built from this site's own fitted equation, the mistake that ends most sub-hour attempts before hairpin 15, and what is actually worth doing in the week beforehand.
20.9 km and 1,534 m, with a forest section, Chalet Reynard and a bare upper slope that each ask for something different. Why negative splitting pays more here than on the Alpe, and the fuelling arithmetic for ninety minutes of climbing.
Three questions decide which plan is right, and hours per week is the one riders get wrong most often. What a week looks like at 3, 5 and 8 hours, where the built-in plans stop working, and a worked route from 2.8 W/kg to under an hour on the Alpe.
The start is harder than the rest of the race combined, and almost everyone goes too deep in the first three minutes. How the categories work, what to do in the opening kilometre, when holding a power-up beats spending it, and how the finish is really decided.
Ranked by how much difference each purchase actually makes, which puts the fan a long way above the bike. Trainers, screens, sensors and cooling, plus three complete builds at different budgets and what each one gives up.
50,000 m of climbing is the headline number, and this is the honest version of how long that takes at a realistic weekly volume. Which unlocks make you faster, which are purely cosmetic, and the point where badge hunting starts costing you fitness.
All eight power-ups, what each does to your numbers, how long it lasts, and the situations where holding one is worth more than using it. The feather is not automatically the right answer on a climb.
XP tracks distance and time rather than effort, which quietly changes almost every decision about how to earn it. How route badges, workouts and long events compare per hour, and why levelling slows down exactly when you start to care.
Indoor FTP usually reads lower than outdoor, and the reasons are heat, continuity and measurement rather than fitness. What a winter of indoor riding does and does not do for your first real ride of the spring.
Cycling burns less than the on-screen calorie figure suggests, and appetite quietly rises to meet most of it. What indoor riding genuinely contributes to fat loss, why cutting hard costs you watts, and the changes worth tracking instead of the scale.