VO2max 4×4-Minute Turbo Intervals

Session Overview

This VO2max turbo session uses four 4-minute intervals at 110–120% of FTP to drive cardiac output to its ceiling and expand your aerobic capacity. It is one of the most evidence-backed interval formats for cycling power development — short enough to maintain maximum effort throughout each rep, long enough to force a genuine VO2max response. Best suited to advanced athletes with a solid aerobic base.

What You’ll Need

• Turbo trainer or smart trainer (power meter strongly recommended)
• Fan for cooling — these intervals generate significant heat
• Water bottle and electrolytes
• Heart rate monitor (optional but useful for tracking cardiac response)

Warm-Up (12 Minutes)

Start with 8 minutes of steady Zone 2 spinning at 90–95rpm. Follow with 2 minutes at sweetspot (90% FTP) to activate the aerobic system, then 2 × 30-second surges at 130% FTP with 30 seconds easy recovery between each. This primes your neuromuscular system and ensures your legs do not feel heavy when the main set begins.

Main Set

Complete 4 intervals at 110–120% of your FTP, with 4 minutes of active recovery at 50% FTP between each effort. The target is to hold consistent power across all four reps — if you go out too hard on rep 1, you will not complete rep 4 at the same effort. Aim for Zone 5 heart rate (>90% HRmax) by the end of each interval.

• Rep 1: 4 minutes at 110–120% FTP — 4 minutes easy recovery at 50% FTP
• Rep 2: 4 minutes at 110–120% FTP — 4 minutes easy recovery at 50% FTP
• Rep 3: 4 minutes at 110–120% FTP — 4 minutes easy recovery at 50% FTP
• Rep 4: 4 minutes at 110–120% FTP — 4 minutes easy recovery at 50% FTP

Cool-Down (8 Minutes)

Spin easy in Zone 1 at 80–90rpm to flush lactate and bring heart rate back to normal. Keep resistance minimal and resist the temptation to stop immediately — the cool-down actively speeds recovery for tomorrow’s session.

Coaching Notes

• Cadence during intervals should be 90–100rpm. Higher cadence shifts cardiac stress upward and increases the VO2max stimulus; grinding a big gear at 70rpm reduces the aerobic benefit.
• Do not start reps at 120% FTP if you have not done this format before. Begin at 110% and add intensity once you know you can hold all four reps evenly.
• To make it easier: reduce to 3 reps with 5-minute recovery. To make it harder: reduce recovery to 3 minutes once you can complete all four reps cleanly.
• RPE target during intervals: 8–9/10. You should feel like you cannot sustain the effort much beyond 4 minutes.