2×20-Minute Threshold Turbo Session

Session Overview

The 2×20-minute threshold session is one of the most effective FTP-building workouts in cycling. By sustaining 20 minutes at or just below your lactate threshold twice, with a short recovery in between, you drive significant cardiovascular and muscular adaptation. Consistent repetition of this session across a build phase is a proven method for improving your FTP and your ability to hold race pace on the bike leg.

• Duration: ~60 minutes total
• Effort: Zone 4 (88–95% FTP) for the main intervals
• Equipment: Turbo trainer or smart trainer (power meter recommended)
• Difficulty: Intermediate

Warm-Up (10 min)

• 10 min easy spin at zone 1–2. Include 3×30 sec at 100 rpm to open up the legs.

Main Set (50 min)

• Interval 1: 20 min at 88–95% FTP (zone 4). Start slightly conservative — the second 20 minutes should feel harder, not the first.
• Recovery: 5 min easy spinning at zone 1.
• Interval 2: 20 min at 88–95% FTP (zone 4). Aim to match or slightly exceed the average power of interval 1.
• Cool-down: 5 min easy spinning.

Coach’s Notes

Pacing is everything here. If you blow up in the final 5 minutes of either interval, you started too hard. A good 2×20 leaves you feeling like you worked hard but could have gone slightly faster — not completely broken. If using a smart trainer in ERG mode, set it to 90% FTP and let the resistance do the work. Perform this session once a week during your build phase, ideally with at least one rest or easy day before and after.