Turbo Descending Blocks: 8-6-4-2 Minute Intervals

Session Overview

This 45-minute turbo session uses a descending block format to push your cycling threshold and top-end power. As the interval duration drops from 8 to 2 minutes, the intensity rises from just below FTP to well above it — training your body to clear lactate quickly and handle hard efforts when it counts. A must-do session for triathletes who want a stronger bike split.

What You’ll Need

• Turbo trainer or smart trainer
• Power meter or RPE scale
• Fan and full water bottle
• Heart rate monitor (optional but useful)

Warm-Up (10 minutes)

10 minutes progressive spin: 5 minutes easy at 90–100rpm, then 3 minutes at moderate resistance, then 2 minutes with 3×10-second high-cadence bursts (110–120rpm) to prime the neuromuscular system. Easy pedalling between bursts.

Main Set

Four descending power blocks — as duration halves, intensity increases. Recovery between each block is roughly half the preceding interval:

• 8 minutes @ 95% FTP (Zone 4) — 4 minutes easy recovery
• 6 minutes @ 100% FTP — 3 minutes easy recovery
• 4 minutes @ 105% FTP — 2 minutes easy recovery
• 2 minutes @ 110–115% FTP (maximal effort) — 2 minutes easy spin

Cool-Down (5 minutes)

5 minutes of very easy spinning at high cadence (90–100rpm) with minimal resistance. Gradually reduce effort over this period. Stretch your hip flexors, quads, and lower back after stepping off the bike.

Coaching Notes

• Start the 8-minute block at 95% FTP — don’t go harder, you need to finish the final 2-minute effort strong
• If you don’t know your FTP, use RPE: 95% = comfortably hard (7–8/10), 110% = very hard (9–9.5/10)
• To make it easier: extend recovery periods by 1 minute each. To make it harder: reduce recovery by 30 seconds
• Target cadence: 85–95rpm throughout — avoid grinding unless deliberately doing strength work