Ironman Bike Training: 10 Threshold Workouts!
Want to ride stronger and crush your Ironman bike split?
Threshold cycling is a crucial part of Ironman training as it helps improve sustained power output, pacing efficiency, and fatigue resistance for the 180 km (112-mile) bike leg.
These sessions focus on Functional Threshold Power (FTP), lactate clearance, and race-specific strength to ensure a strong and efficient ride.
1. Classic Threshold Intervals
Purpose: Improves FTP and ability to sustain hard efforts.
Session:
Warm-up: 15 min easy spin
Main Set:
4 x 10 min at 95–100% FTP (Zone 4), 5 min easy spin recovery
Cool-down: 10 min easy spin
Focus: Maintaining a steady effort, controlling heart rate, and focusing on smooth pedaling.
2. Sweet Spot Over-Unders
Purpose: Trains the ability to handle pace surges and recover efficiently.
Session:
Warm-up: 15 min easy spin
Main Set:
5 x (3 min at 105% FTP + 3 min at 90% FTP), 5 min recovery
Cool-down: 10 min easy spin
Focus: Managing effort fluctuations without excessive fatigue.
3. Race-Pace Threshold Simulation
Purpose: Builds endurance at race-specific intensities.
Session:
Warm-up: 15 min easy spin
Main Set:
3 x 20 min at 85–90% FTP (upper Zone 3–low Zone 4), 5 min easy spin recovery
Cool-down: 10 min easy spin
Focus: Aerodynamic position, fueling, and power consistency.
4. Progressive Threshold Build
Purpose: Teaches controlled pacing with a strong finish.
Session:
Warm-up: 15 min easy spin
Main Set:
4 x 12 min:
1st: 88% FTP (upper Zone 3)
2nd: 92% FTP
3rd: 95% FTP
4th: 98% FTP
Cool-down: 10 min easy spin
Focus: Gradual intensity increase while keeping cadence smooth (85–95 RPM).
5. High-Cadence Threshold Ride
Purpose: Improves efficiency and reduces leg fatigue.
Session:
Warm-up: 15 min easy spin
Main Set:
4 x 8 min at 95% FTP, maintaining 100+ RPM, 4 min easy spin recovery
Cool-down: 10 min easy spin
Focus: Pedaling efficiency and reducing energy waste.
6. Hill Climb Threshold Efforts
Purpose: Builds leg strength and muscular endurance.
Session (outdoors or simulated on trainer):
Warm-up: 15 min easy spin
Main Set:
5 x 6 min climbs at FTP or slightly above (Zone 4–5), low cadence (65–75 RPM), 4 min easy spin recovery
Cool-down: 10 min easy spin
Focus: Developing sustained power output and fatigue resistance.
7. Threshold & Tempo Combo Ride
Purpose: Combines steady endurance work with high-intensity threshold efforts.
Session:
Warm-up: 15 min easy spin
Main Set:
30 min at Ironman race pace (Zone 3, ~80–85% FTP)
4 x 5 min at 100–105% FTP, 3 min recovery
15 min at Ironman race pace
Cool-down: 10 min easy spin
Focus: Practicing race-day fueling and intensity control.
8. Long Ride with Threshold Surges
Purpose: Trains the ability to recover from efforts while maintaining endurance.
Session:
Warm-up: 5 min easy spin
Main Set:
3–4 hours total ride time
Every 30 min, insert 5 min at 100% FTP
Last 30 min at Ironman race pace
Cool-down: 10 min easy spin
Focus: Managing effort surges without blowing up later.
9. Descending Threshold Intervals
Purpose: Builds the ability to push harder as fatigue increases.
Session:
Warm-up: 15 min easy spin
Main Set:
3 x 12 min at 98%, 100%, and 102% FTP (slightly harder each rep), 5 min recovery
Cool-down: 10 min easy spin
Focus: Holding form and pushing strong despite increasing intensity.
10. Taper Threshold Tune-Up (7–10 days pre-race)
Purpose: Keeps sharpness without excessive fatigue.
Session:
Warm-up: 15 min easy spin
Main Set:
3 x 6 min at 100% FTP, 3 min easy spin recovery
Cool-down: 10 min easy spin
Focus: Feeling fast, efficient, and race-ready.
Mini FAQ: Threshold Bike Training for Ironman
What is threshold power on the bike?
Threshold power is the highest average power you can sustain for about an hour—typically measured as Functional Threshold Power (FTP).
Why is threshold training important for Ironman cyclists?
It boosts your aerobic capacity, muscular endurance, and ability to hold a steady effort for long periods—crucial for a strong bike split.
How often should I do threshold bike sessions?
Once per week during your build phase is ideal. Combine with long rides, tempo efforts, and recovery rides for balance.
How long should threshold intervals be?
Intervals typically range from 6 to 20 minutes. Start with shorter reps and increase duration as your fitness builds.
Can I do threshold sessions indoors?
Absolutely. Indoor training allows for precise control over intensity and is great for structured threshold work, especially using a smart trainer or power meter.
Final Thoughts
These threshold bike sessions improve sustained power, race-day pacing, and fatigue resistance. Integrate 1–2 per week alongside endurance and recovery rides to maximize your Ironman cycling performance.
Hit these sessions weekly and watch your power, speed, and confidence skyrocket.
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.