10 Key Ironman 70.3 Threshold Brick Sessions!
Want to crush the run without fading off the bike?
Threshold brick sessions are some of the most effective workouts for Ironman 70.3 athletes looking to improve speed, endurance, and resilience.
These sessions focus on sustained efforts at or just below lactate threshold, helping you build the ability to sustain high-intensity work across the bike and run.
Why Threshold Bricks Matter for Ironman 70.3
• Improves Aerobic Capacity – Helps sustain higher power and pace for longer.
• Enhances Bike-to-Run Adaptation – Reduces the heavy-leg feeling off the bike.
• Builds Mental Toughness – Prepares you for race-day discomfort and pacing control.
• Optimises Pacing Strategy – Trains your body to efficiently manage effort levels.
Here are 10 key threshold brick sessions to elevate your 70.3 performance:
1. Classic Bike-Run Tempo Brick
Purpose: Build race-specific endurance at Olympic distance intensity.
Warm-Up: 10 minutes easy spin
Main Set: Bike 30K at 80–85% FTP
Run Transition: 5 minutes easy jog
Run 5K at 80–85% of threshold pace
Cool-Down: 10 minutes easy jog
2. Progressive Bike to Fast Finish Run
Purpose: Teach pacing and finishing strong under fatigue.
Warm-Up: 10 minutes easy spin
Main Set: Bike 30K progressive—10K at 75%, 10K at 80%, 10K at 85% FTP
Run Transition: 5 minutes easy jog
Run 5K, with the last 2K at 90% effort
Cool-Down: 10 minutes easy jog
3. Race-Paced Run Off the Bike
Purpose: Practice pacing and smooth transitions.
Warm-Up: 10 minutes easy spin
Main Set: Bike 20K at race pace (85% FTP)
Run Transition: 5 minutes easy jog
Run 5K at goal race pace
Cool-Down: 10 minutes easy jog
4. Over/Under Threshold Brick
Purpose: Adapt to pace variability and stay strong.
Warm-Up: 10 minutes easy spin
Main Set: Bike 3 x 10K — first and third at 90% FTP, second at 80% FTP
Run Transition: 5 minutes easy jog
Run 3K at 90% effort
Cool-Down: 10 minutes easy jog
5. Short & Sharp Brick
Purpose: Stimulate race effort in a short, efficient session.
Warm-Up: 10 minutes easy spin
Main Set: Bike 15K at 85–90% FTP
Run Transition: 5 minutes easy jog
Run 3K at 85–90% effort
Cool-Down: 10 minutes easy jog
6. Rolling Hills Strength Brick
Purpose: Build muscular endurance and strength for hilly courses.
Warm-Up: 10 minutes easy spin
Main Set: Bike 30K on hilly terrain at 75–85% FTP
Run Transition: 5 minutes easy jog
Run 6K on hills at 80–85% effort
Cool-Down: 10 minutes easy jog
7. Swim-Bike Tempo Combo
Purpose: Practice settling into bike pace after the swim.
Warm-Up: 10 minutes easy swim
Main Set: Swim 1.5K at race effort
10 minutes easy spin on the bike
Bike 30K at 80–85% FTP
Cool-Down: 10 minutes easy spin
8. Broken Run Brick
Purpose: Improve ability to run strong under fatigue with broken intervals.
Warm-Up: 10 minutes easy spin
Main Set: Bike 30K at 80–85% FTP
Run Transition: 5 minutes easy jog
Run 3 x 2K at 85–90% effort with 60 seconds rest between reps
Cool-Down: 10 minutes easy jog
9. Double Brick Session
Purpose: Simulate race fatigue with repeated transitions.
Warm-Up: 10 minutes easy spin
Main Set:
Bike 15K at 85% FTP
Run Transition: 5 minutes easy jog
Run 3K at 85% effort
Bike 15K at 85% FTP
Run Transition: 5 minutes easy jog
Run 3K at 85% effort
Cool-Down: 10 minutes easy jog
10. Threshold Push Brick
Purpose: Increase lactate threshold and mental toughness.
Warm-Up: 10 minutes easy spin
Main Set: Bike 4 x 8K at 90% FTP with 2 minutes easy between efforts
Run Transition: 5 minutes easy jog
Run 5K with the final 1K at 90% effort
Cool-Down: 10 minutes easy jog
Tips for Executing Threshold Bricks
Fuel Strategically – Threshold sessions are demanding; practice race nutrition.
Control Pacing – Stay at prescribed efforts to avoid burnout.
Recover Well – Schedule proper rest after these high-intensity workouts.
Simulate Race Conditions – Use race-day gear and transitions.
Incorporate these threshold brick sessions into your training to develop race-ready fitness and confidence for your next Ironman 70.3!
Ready to turn every brick into a breakthrough on race day?
Consult a healthcare professional before starting any fitness plan to ensure it is safe and appropriate for your individual needs.