Classic 2x20
75 min · 69-84 TSS · IF 0.78 · 88-95% FTP · Zone 4 (Sweet Spot)
What this workout does
The gold standard for building threshold power. Two sustained efforts that challenge your body to adapt at the intensity where fitness gains are greatest.
Long intervals at 90-95% FTP maximize time near threshold, the intensity that drives the biggest gains in lactate clearance and sustainable effort. Twenty-minute blocks force your aerobic system to work at its ceiling, improving mitochondrial density and fuel efficiency. A cornerstone of any build phase, best ridden fresh early in the week.
How to ride it
Indoor / trainer
Warm up 15min. 2x20min at 90-95% FTP with 5min easy between. Cool down 10min. Target 90-95 RPM.
Outside
Choose a quiet road or steady loop where you can ride 20 minutes without stops. Hold 90-95% FTP - breathing deep, speaking only in short sentences - and spin easy for 5 minutes between efforts.
Workout structure (75 min)
- Warm-up 15m 55% 2x - Effort 20m 93% 93rpm - 5m 55% - Cool-down 10m 55%
Targets are a percentage of FTP. This is the same shorthand the free workout builder understands — paste it there to edit any step, or download the workout for Zwift, Garmin or any smart trainer.
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