What muscular endurance actually means on the bike
Muscular endurance is not the same as fitness, and it is not the same as strength. Most riders conflate the two, which is why most riders plateau. Fitness — measured by VO2max or FTP — tells you how powerful your engine is. Muscular endurance tells you how long your legs can produce that power before they stop cooperating. The two qualities are related, but they respond to different training stimuli and degrade at different rates.
On a practical level, muscular endurance shows up during a 40-minute climb where you need to hold a steady 270 watts all the way to the top, or across a two-hour criterium where you keep accelerating out of corners without your quads turning to concrete. The moment your legs feel heavy — not breathless, not out of oxygen, but just heavy and unresponsive — that's a muscular endurance problem. Your cardiovascular system still has capacity; it's the muscle fibres that are waving the white flag.
Physiologically, what you're developing is the ability of your type IIa muscle fibres to sustain repeated, forceful contractions without crossing into glycolytic burn-out territory. Well-trained muscular endurance means you fatigue less at threshold power, recover faster between hard efforts mid-race, and hold a bigger gear later into a long ride. That's the return on investment. It's also why tempo training is the most direct entry point into this quality — tempo sits exactly at the intensity where muscular demand starts to climb faster than aerobic demand, making it a direct stimulus for the adaptations you're after.
The zone and the effort: where this training actually lives
The standard framing puts muscular endurance in Zone 3 — roughly 76–90% of your FTP, labelled Tempo in most power-zone systems. That's accurate as a starting point, but it misses nuance. Pure Tempo riding at a comfortable 90–95 rpm does build aerobic capacity and glycogen storage, but it does relatively little to challenge the muscular side of the equation. To genuinely drive muscular endurance adaptations, you need to add either duration or force — often both.
Low-cadence work — pedalling at 50–60 rpm at or just below your FTP — is one of the most effective tools here. When you drop your cadence, the torque per pedal stroke goes up, and you recruit significantly more muscle fibre per revolution. The cardiovascular load stays moderate (you're not pushing a 120% VO2max effort), but the muscular demand is high. Over time, this signals type IIa fast-twitch fibres to behave more like their slow-twitch counterparts — more mitochondria, better oxygen utilisation, slower to fatigue. A 2025 systematic review in the European Journal of Applied Physiology confirmed that high-force work at aerobic intensities is particularly effective for improving these physiological determinants in cyclists.
Sweet spot (88–94% FTP) is the other key intensity. It sits at the upper edge of muscular endurance work and is time-efficient in a way that pure Zone 3 tempo is not. Three twelve-minute efforts at sweet spot stresses your muscles more meaningfully than three hours of easy Zone 2, and it does so in a form that's repeatable twice a week without wrecking your training schedule. The key distinction: at sweet spot, you're starting to really recruit those fast-twitch aerobic fibres rather than just teasing them. That's a more powerful stimulus for the quality you want to develop.
How to structure a muscular endurance block
A well-designed muscular endurance session doesn't need to be elaborate. The variables that matter are intensity, cadence, interval duration, and total accumulated work. For a rider building this quality for the first time, a solid starting session looks like four intervals of ten minutes at 85–90% FTP, cadence deliberately held at 60–65 rpm, with four minutes of easy spinning recovery between efforts. Total hard work: forty minutes. That's a session with genuine training value that doesn't leave you destroyed for the rest of the week.
Progression should come from extending interval duration before increasing intensity. Moving from 10-minute to 15-minute blocks at the same power and cadence is a more sustainable approach than jumping from 85% to 95% FTP prematurely. The muscular stress is cumulative — the later intervals in a set are where the real adaptation happens, and if you've gone too hard in the opening efforts, you'll either bail on the final interval or compensate by spinning your cadence up to offload the work onto your cardiovascular system. That side-steps the whole point of the session. Keep the cadence anchored and let the discomfort arrive on schedule.
Two sessions per week is enough for most amateur riders, separated by at least 48 hours. If you're also running VO2max intervals or threshold work in your week, schedule muscular endurance sessions on lower-intensity days and treat them as complementary. There's one underrated setting for this kind of work: a sustained climb. A genuine 6–10% gradient at 55 rpm for 8 minutes produces muscular tension that flat interval work simply doesn't replicate. If you race or ride in hilly terrain, low-cadence climbing intervals belong in your rotation — they train muscular endurance in the exact context where you'll need to use it.
What goes wrong — and how to fix it before it derails the block
The most common mistake is doing these sessions at the wrong cadence. Riders who normally train with a high, efficient pedalling rhythm will unconsciously spin up when the intervals get hard. The moment you're at 85 rpm and 88% FTP, you've shifted the stress away from the muscular system and towards the cardiovascular one. It's still a useful training stimulus — just not the adaptation you came for. Lock your cadence field on your head unit. Be deliberate. When 60 rpm feels uncomfortable at 87% FTP, that discomfort is doing the work; it's not a sign you should spin faster.
The second mistake is underestimating the recovery debt. Muscular endurance sessions are deceptively fatiguing. The cardiovascular load is moderate, so you feel fine during the effort — but the muscular load accumulates in a way that tends to surface 18–24 hours later. Riders who stack these sessions too close together often find their power drifting down across the week and assume they're overreaching. Usually they're just locally fatigued and need a day of easy spinning to absorb the stress. Trust the structure and resist the urge to add more.
Let's be direct about something: most riders ignore cadence prescription entirely, default to whatever feels natural, and then wonder why they can't sustain power on long climbs or feel "full" in their legs two hours into a sportive. The answer is not more fitness work. It's deliberate muscular endurance training combined with smart cadence periodisation. High-cadence drills and low-cadence muscular endurance intervals belong in the same training plan, on different days, addressing opposite ends of the efficiency spectrum. Neither alone is enough.
Related reads
Tempo training for cyclists
Low-cadence training for climbing
High-cadence drills for cyclists
Sources
- Rønnestad, B.R. et al. (2021). "A Comparison of the Effect of Strength Training on Cycling Performance between Men and Women." International Journal of Environmental Research and Public Health. PMC8006227.
- Vikmoen, O. & Rønnestad, B.R. (2025). "Heavy strength training effects on physiological determinants of endurance cyclist performance: a systematic review with meta-analysis." European Journal of Applied Physiology. doi:10.1007/s00421-025-05883-2
- TrainerRoad (2024). "Cycling Power Zones: Training Zones Explained." trainerroad.com/blog/cycling-power-zones-training-zones-explained
- CTS (2023). "Science of Cycling Cadence: Economy, Efficiency and How to Train Low and High Cadence." trainright.com/science-of-cycling-cadence-training