Crush Race Day: 10 Threshold Brick Sessions for Ironman!
Ready to run strong off the bike and crush your Ironman finish line?
Brick workouts—combining cycling and running—are essential for Ironman athletes. But to take your performance to the next level, threshold brick sessions should be a key part of your race build.
These high-quality sessions are designed to improve your ability to sustain effort at race intensity, increase fatigue resistance, and sharpen your mental game for race day.
In this post, you’ll find 10 powerful threshold brick sessions tailored for Ironman 70.3 and full-distance training. Each one is designed to simulate the demands of racing and help you handle the bike-to-run transition like a pro.
Why Threshold Brick Workouts Matter
Threshold bricks push you to train near your functional threshold power (FTP) on the bike and your lactate threshold pace on the run. These are the intensities where your body is working hard but sustainably. Exactly what’s needed during long-course racing.
Benefits of threshold brick training:
Enhances your ability to hold strong effort off the bike
Teaches you to process lactate efficiently
Builds resilience for the final stretch of the race
Reinforces race nutrition and pacing strategies
Whether you’re a first-timer or aiming for a new personal best, adding these bricks once per month can elevate your Ironman training.
10 Threshold Brick Sessions to Add to Your Ironman Training Plan
Each session includes a 10-minute warm-up and cool-down, plus a 5-minute easy jog between the bike and run to simulate transition and allow your body to reset.
1. Classic Threshold Brick
Bike: 10 min warm-up → 3 x 15 min @ 85–90% FTP (5 min recovery)
Run: 5 min easy jog → 3 x 1 mile @ threshold pace (2 min recovery) → 10 min cool-down
Purpose: Improves sustained power and speed off the bike.
2. Over-Under Brick
Bike: 10 min warm-up → 4 x 10 min (2 min @ 95% FTP + 2 min @ 80% FTP)
Run: 5 min easy jog → 4 x 5 min @ slightly faster than race pace → 10 min cool-down
Purpose: Trains your body to clear lactate while maintaining a strong pace.
3. Progressive Build Brick
Bike: 10 min warm-up → 60 min progressing from 75% to 90% FTP
Run: 5 min easy jog → 30 min starting at Ironman pace, finishing at 10K pace → 10 min cool-down
Purpose: Sharpens pacing and finishing strength under fatigue.
4. Race-Pace Simulation Brick
Bike: 10 min warm-up → 90 min @ 80–85% FTP
Run: 5 min easy jog → 10K @ goal race pace → 10 min cool-down
Purpose: Rehearses pacing, nutrition, and mental strategy in race-like conditions.
5. VO2 Max Booster Brick
Bike: 10 min warm-up → 5 x 5 min @ 105% FTP (3 min recovery)
Run: 5 min easy jog → 5 x 3 min @ 5K pace (2 min recovery) → 10 min cool-down
Purpose: Builds top-end fitness and your ability to respond to surges or hills.
6. Long Steady-Tempo Brick
Bike: 10 min warm-up → 3 hours @ 75–85% FTP
Run: 5 min easy jog → 45 min @ 80–85% threshold pace → 10 min cool-down
Purpose: Builds endurance while maintaining strong intensity.
7. Reverse Threshold Brick
Run: 10 min warm-up → 30 min @ 85–90% threshold pace → 10 min cool-down
Bike: 10 min warm-up → 60 min @ 80–85% FTP → 10 min cool-down
Purpose: Trains your legs to perform when pre-fatigued from the run—a great variation for mental and physical toughness.
8. Hill Strength Brick
Bike: 10 min warm-up → 4 x 12 min uphill @ 90% FTP
Run: 5 min easy jog → 4 x 800m uphill @ threshold effort → 10 min cool-down
Purpose: Builds strength, power, and muscular endurance for hilly courses.
9. Short & Sharp Brick
Bike: 10 min warm-up → 6 x 5 min @ 90–95% FTP (2 min recovery)
Run: 5 min easy jog → 6 x 1K @ threshold pace → 10 min cool-down
Purpose: Improves your ability to handle repeated high-intensity efforts back-to-back.
10. Double Brick
Bike 1: 10 min warm-up → 45 min @ 85% FTP
Run 1: 5 min easy jog → 5K @ threshold pace → 10 min cool-down
Bike 2: 10 min warm-up → 45 min @ 85% FTP
Run 2: 5 min easy jog → 5K @ threshold pace → 10 min cool-down
Purpose: Simulates race-day fatigue and reinforces pacing discipline over a long day.
Final Tips for Threshold Brick Training
Fuel like it’s race day: These sessions burn through glycogen. Use them to practice your race nutrition plan.
Balance intensity: Follow bricks with easier days or recovery workouts to ensure full adaptation.
Be consistent: Aim for one threshold brick per week during your race-specific training phase.
Taper smart: Reduce volume but maintain some intensity in the final 2–3 weeks before your race.
Mini FAQ: Threshold Brick Training
How often should I do threshold bricks?
Once a month is ideal during your Ironman build. Combine with VO2 and endurance work for balanced fitness.
Can beginners use these sessions?
Yes—but scale the duration or intensity. Focus on form, consistency, and recovery over maximal effort.
Are these good for full Ironman or just 70.3?
They’re ideal for both. Adjust the run and bike durations to suit your goal race distance and fitness level.
Final Thoughts
By integrating these threshold brick sessions into your Ironman training plan, you’ll build race-ready fitness that goes far beyond basic endurance. Power, pacing, and mental sharpness—you’ll have it all when it counts most.
Which of these threshold brick sessions will you conquer first?
Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.