15/15 Microbursts, 3 x 12
Three sets of 12 x 15 seconds at 130 to 140% of FTP and 15 seconds easy, microbursts that keep the load on the aerobic system.
- Duration
- 51 min
- Effort
- 48
- Level
- Intermediate
- Focus zone
- VO2max
Your values
Targets relative to your threshold values. Enter your values to see absolute numbers.
| # | Step | Length | Target |
|---|---|---|---|
| 1 | Warm-upEndurance Easy spin, build gradually | 10 min | 45 → 72% FTP54 → 74% HRmax |
| 2 | Warm-upEndurance Steady and easy | 5 min | 60-70% FTP65-78% HRmax |
| 12 ×Repeat these steps | |||
| 3.1 | IntervalVO2max Quick, seated, high rpm | 15 s | 130-140% FTP92-98% HRmax |
| 3.2 | RecoveryRecovery Easy spin | 15 s | 45-55% FTP75-90% HRmax |
| 4 | RecoveryRecovery Easy spin, set 2 next | 4 min | 40-55% FTP50-65% HRmax |
| 12 ×Repeat these steps | |||
| 5.1 | IntervalVO2max Quick, seated, high rpm | 15 s | 130-140% FTP92-98% HRmax |
| 5.2 | RecoveryRecovery Easy spin | 15 s | 45-55% FTP75-90% HRmax |
| 6 | RecoveryRecovery Easy spin, set 3 next | 4 min | 40-55% FTP50-65% HRmax |
| 12 ×Repeat these steps | |||
| 7.1 | IntervalVO2max Quick, seated, high rpm | 15 s | 130-140% FTP92-98% HRmax |
| 7.2 | RecoveryRecovery Easy spin | 15 s | 45-55% FTP75-90% HRmax |
| 8 | Cool-downRecovery Easy spin, let the legs settle | 10 min | 60 → 40% FTP65 → 50% HRmax |
About this workout
Microbursts break VO2max work into very short pieces. Each 15 second effort is hard but too short to drain the legs, and the 15 second breaks are too short for heart rate and breathing to settle. Over a 6 minute set the aerobic system works at a high level while the muscles get a steady stream of short breaks.
Ride the efforts at 130 to 140% of FTP and recover at about 50%. Three sets of 12 with 4 minutes between them add up to 9 minutes of work. The power is higher than in longer intervals, so cadence matters. Keep it at 95 to 110 rpm so the efforts come from leg speed rather than force.
Microbursts suit riders who struggle to hold longer VO2max efforts, criterium riders and anyone coming back to intensity. Progress by adding a fourth set or by moving on to 30/15 intervals.
Tips
- Use ERG mode or a fixed gear, since shifting at this rhythm is hard.
- Stay seated and keep the upper body still.
- If heart rate does not climb by the end of a set, the efforts are too easy.
Good forCriteriumRoad raceGeneral fitness
Season phaseBuildPeak