Ironman Race Watts: 3×45-Minute Turbo Trainer Session

Session Overview

This advanced turbo session uses three long sustained blocks at your Ironman race wattage — typically 65–70% FTP — to build the specific muscular endurance needed for the 180km bike leg. With warm-up and cool-down the total session time is approximately 2 hours 30 minutes. Treat each fuelling break between blocks as race-day nutrition practice.

What You’ll Need

• Smart trainer or power meter-equipped bike
• Powerful fan for cooling (critical for this duration)
• Minimum 2 × 750ml bottles — this is fuelling practice too
• Chamois cream for a session this long

Warm-Up (20 minutes)

10 minutes Zone 1 easy spinning, then 5 × 1-minute builds from Zone 2 to Zone 4 with 1 minute easy between each. Finish with 5 minutes at Zone 2 before starting the first block.

Main Set

Your Ironman race watts is approximately 65–70% of your FTP. To calculate: multiply your 20-minute test power by 0.95, then multiply by 0.67.

• Block 1: 45 minutes at Ironman race watts, 85–90 rpm target cadence
• Recovery: 10 minutes Zone 1 spinning + eat and drink (practice your race nutrition)
• Block 2: 45 minutes at Ironman race watts, focus on holding aero position
• Recovery: 10 minutes Zone 1 spinning + refuel
• Block 3: 45 minutes at Ironman race watts — maintain the watts even as fatigue builds

Cool-Down (15 minutes)

Easy Zone 1 spin for 10 minutes, then 5 minutes off the bike with hip flexor and quadriceps stretching. Don’t skip this — your back and hips will need it after 2+ hours in the saddle.

Coaching Notes

• Aim for 60–90g carbohydrates per hour from the start of the session — this also trains your gut for race day
• If you can’t hold watts in block 3, reduce by 5W rather than abandoning the block entirely
• This session is excellent preparation for IRONMAN UK Bolton and Challenge Roth — use it 4–8 weeks out
• Advanced athletes preparing for a full Ironman: extend each block to 60 minutes with the same 10-minute recovery