Why pacing is the variable most riders get wrong
You can have the fitness, the training, the right equipment — and still lose significant time to a rider who simply manages their effort better. Pacing is one of those unglamorous topics that doesn't generate much excitement, but in terms of time saved per watt of effort, it's one of the highest-leverage things you can work on. Let's be honest: most amateur cyclists go too hard at the start of a climb, hit the redline halfway up, and spend the next ten minutes grinding through the consequences. The fitness was there. The execution wasn't.
The good news is that pacing is a learnable skill, and — unlike VO2max or lactate threshold — you can improve it immediately. No six-week training block required. You just need to understand what's actually happening physiologically and physically when you distribute effort differently across a course.
The physics that most riders ignore
Here's a principle that changes how you think about pacing: wind resistance is exponential, not linear. Every small increase in speed costs a disproportionately large amount of power to sustain. Going from 35 km/h to 38 km/h on flat ground demands far more watts than going from 20 km/h to 23 km/h. This means that if you have a fixed amount of energy to spend across a course, you get the best return on investment by spending that energy where your speed is already low — which is on the climbs.
On a climb, you're moving slowly enough that air resistance is almost irrelevant. An extra 20 watts of effort on a 6% gradient translates into a meaningful speed gain because nothing is fighting you aerodynamically. On a flat road at 40 km/h, those same 20 watts disappear almost entirely into the wind. This is why mathematically optimal pacing on a mixed course always involves pushing harder on ascents and slightly easing off on flats and descents — not because you're saving legs, but because that's where your effort generates the most return.
A practical implication that riders miss: don't stall over the top of a climb. The transition from the summit to the descent is exactly where many cyclists back off instinctively. But carrying speed over the crest and into the descent buys you significant free time — whereas soft-pedalling over the top and then building back up costs you that advantage entirely.
Aerobic versus anaerobic pacing: what the research shows
A useful way to think about pacing is through the lens of your two main energy systems. Your aerobic engine can sustain effort for hours, regulated by oxygen delivery and metabolic efficiency. Your anaerobic system can produce explosive power but generates lactate rapidly — and when that acid accumulates faster than you can clear it, power output degrades sharply and involuntarily. Good pacing, fundamentally, is about controlling when and how aggressively you draw on that anaerobic reserve.
Research on 4 km time trials — a format where the margin between winning and blowing up is brutally thin — shows that the distribution of anaerobic energy contribution changes more between pacing strategies than the aerobic contribution does. Your aerobic engine is fairly stable; it's the anaerobic system that either helps you or kills you depending on when you deploy it. Going too hard too early forces you to rely on anaerobic capacity before your aerobic system is fully engaged, and then you have nothing left when you need it most. A measured start that feels almost conservative — and feels that way because it should — lets you build momentum, stay aerobically dominant for longer, and then unleash whatever anaerobic capacity remains when the finish line is close enough to matter.
This principle holds for longer events too, just on a different timescale. In a three-hour sportive with a 20-minute climb at hour two, the equivalent mistake is going so hard in the opening hour that your glycogen stores are depleted before you reach the hardest section. The body's ability to buffer metabolic disturbance decreases as you accumulate fatigue — which means the cost of going too hard early compounds over time in a way that's hard to recover from.
How to actually apply this with a power meter
If you train and race with a power meter, you have everything you need to implement good pacing immediately. The key is to use normalized power as a guide rather than average power. Average power penalises you for high-effort sections that are actually physiologically efficient; normalized power accounts for the metabolic cost of variability and gives you a better picture of how hard the ride actually felt on your body.
Before a target event, study the course profile and identify the critical sections: the long climbs, the punchy short rises, the headwind stretches, the descent that precedes the final climb. Then decide — consciously, in advance — what power you'll hold on each section. For the climbs, you should typically be riding somewhere between your sweet spot and threshold power if the effort is longer than five minutes. For shorter punchy rises, going over threshold briefly is fine, but only if the course rewards it and only if you can recover before the next demanding section. For the flats, especially with a tailwind, back off and let the terrain do the work.
A variable intensity ratio (VI) — the ratio of normalized power to average power — tells you how well you paced. A ratio close to 1.0 means you rode smoothly and efficiently. A ratio above 1.05 suggests you had a lot of unnecessary spikes, attacks, or surges that cost you more metabolically than they benefited you in speed. If your VI on a sportive is 1.10 or above, there's a good chance that some of your effort was burned in places where the physics didn't reward it.
For those without a power meter, heart rate works as a rough guide, but with a caveat: cardiac drift means heart rate climbs over time even at steady effort, and it also responds slowly to changes in intensity. Use it as a long-term indicator — if your heart rate is 10 beats per minute higher than expected 40 minutes into a climb, that's a signal you started too hard — but don't micromanage it moment to moment. Rate of perceived exertion (RPE) remains surprisingly reliable once you've calibrated it through enough training rides. If the climb feels very hard at kilometre one of a twelve-kilometre ascent, you're going too fast. Full stop.
If you want a coach or an algorithm to do the course analysis and power targeting for you, LeCoach builds personalized pacing guidance into your training plans, so you're not having to reverse-engineer this from first principles before every event.
The mental side of pacing nobody talks about
Knowing the right pace and actually executing it under race conditions are two different things. The most common failure mode is social — you go too hard because the rider in front of you went too hard, or because the start of a sportive feels festive and fast and it seems wrong to hold back. Group dynamics override individual pacing plans constantly. The way to resist this is to decide on your effort ceiling before the gun goes off, treat the first twenty minutes of any event as deliberately conservative, and let the riders who burned matches at the start come back to you in the final hour.
Another underappreciated mental trap is over-correcting after a forced surge. If you've spiked your power unexpectedly — chasing a wheel, responding to an attack, cresting a rise faster than planned — the instinct is to immediately soft-pedal to compensate. But this creates its own inefficiency: you lose speed, lose momentum, and your average power drops. The better response is to bring effort back to target gradually over sixty to ninety seconds, rather than swinging to a near-zero power output. Smooth transitions between intensities are almost always faster than reactive over-compensations.
Pacing is, at its core, about confidence in your own plan and the discipline to execute it even when everything around you is telling you to do otherwise. That confidence comes from having tested your pacing targets in training — knowing what threshold feels like at the two-hour mark, knowing how a controlled climb sits in your legs versus one where you went out too hard. The more deliberately you practice pacing in training, the more automatic good execution becomes on race day.
For more on how to structure your training around events and build the fitness that makes good pacing possible, see the guide on cycling periodization and season building.
Sources: Menaspa et al. (2013), Pacing Strategy in Short Cycling Time Trials; Mauger et al. (2012), Exploring the Performance Reserve; Corbett et al. (2023), Effect of Different Pacing Strategies on 4-km Cycling Time Trial Performance, PMC9828863; Lucia et al. (2007), Distribution of Power Output During Cycling, PubMed 17645369.