Forty-Twenty
65 min · 56-68 TSS · IF 0.75 · 110-120% FTP · Zone 5+ (VO2max)
What this workout does
Forty seconds on, twenty seconds off, in three sets of eight. The longer work bouts bite harder than 30/30s while the short recoveries keep your aerobic system at full stretch - a race-hardening session.
Forty seconds at 110-120% FTP with only 20s off tilts the work-rest ratio so each set becomes one long semi-continuous effort near maximal oxygen uptake. It also trains clearing lactate while still riding hard, not just while resting. A natural step up from 30/30s once those stop feeling threatening.
How to ride it
Indoor / trainer
Warm up 15min with 3 short openers. 3 sets of 8x(40s at 110-120% FTP / 20s easy). 5min easy between sets. Cool down 10min.
Outside
A quiet flat road with a repeating 1min timer: 40s at 110-120% FTP, 20s soft-pedal. Hold your line and your rhythm - the set only works if the recoveries stay short and the effort stays honest.
Workout structure (65 min)
- Warm-up 15m 55% 3x - Opener 30s 110% - 1m 30s 55% 8x - Effort 40s 115% - 20s 45% - 5m 55% 8x - Effort 40s 115% - 20s 45% - 5m 55% 8x - Effort 40s 115% - 20s 45% - 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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