Summary:
A threshold session gives a bike ride a specific task, with periods of Zone 4 cycling separated by recovery or combined with other intensities. These ten examples offer workout ideas for Ironman 70.3 preparation, explaining the purpose of each session and the riding involved.
Working With a Threshold Target on the Bike
A target can give your cycling direction, but following it takes more than watching a number. During a threshold effort, you are also judging whether the output feels sustainable for the work ahead. The first repetition gives you an opportunity to make that assessment before committing to the rest of the set. Aim to finish it with a sense that you could return to the same effort after the prescribed recovery.
The ten sessions below offer different ways to organise threshold riding within your Ironman 70.3 training. Read the purpose of each workout before choosing, then look at how the harder efforts are distributed. A longer interval asks you to concentrate for more time without a break, while repeated shorter efforts give you more frequent opportunities to reset. Your recent cycling can help you decide which challenge suits you and how much of the session to complete.
Our Where Do Training Zones Fit Into Ironman 70.3 Preparation? guide explains how to use the different intensities across your training. Our Bike Calculators can help you establish cycling power or heart rate ranges for these workouts.
10 Threshold Bike Sessions for Ironman 70.3 Training
1. Classic Threshold Intervals
Purpose: Accumulates threshold cycling through five-minute repetitions, with recovery helping you maintain the intended effort across the full set.
Warm-Up: 15 min easy spin
Main Set: 5 × 5 min @ Zone 4 (3 min easy spin between)
Cool-Down: 15 min easy spin
2. Alternating Threshold and Tempo
Purpose: Follows each threshold effort with tempo riding, giving you practice reducing your output while continuing to work before taking an easier recovery.
Warm-Up: 15 min easy spin
Main Set: 4 × (3 min @ Zone 4 → 2 min @ Zone 3) (3 min easy spin between sets)
Cool-Down: 15 min easy spin
3. Continuous Threshold Effort
Purpose: Provides an uninterrupted threshold block, asking you to judge your opening effort and maintain controlled output throughout the twenty minutes.
Warm-Up: 15 min easy spin
Main Set: 20 min continuous @ Zone 4
Cool-Down: 15 min easy spin
4. Long Threshold Blocks
Purpose: Divides sustained threshold riding into two extended efforts, with an easier recovery before returning to the same intensity for the second block.
Warm-Up: 15 min easy spin
Main Set: 2 × 15 min @ Zone 4 (5 min easy spin between)
Cool-Down: 15 min easy spin
5. Threshold Pyramid
Purpose: Varies the length of each repetition while keeping the intensity at threshold, giving you practice managing the effort as the intervals lengthen and shorten.
Warm-Up: 15 min easy spin
Main Set: 4 min → 6 min → 8 min → 6 min → 4 min @ Zone 4 (2 min easy spin between)
Cool-Down: 15 min easy spin
6. Tempo Into Short Threshold Repeats
Purpose: Places short threshold repetitions after a sustained tempo block, using regular recoveries to separate the harder efforts in the second part of the session.
Warm-Up: 15 min easy spin
Main Set:
20 min @ Zone 3
3 min easy spin before moving into
5 × 2 min @ Zone 4 (2 min easy spin between)
Cool-Down: 15 min easy spin
7. Sustained Tempo Into Threshold
Purpose: Finishes a continuous tempo block with threshold riding, challenging you to increase the intensity after a substantial period of purposeful cycling.
Warm-Up: 15 min easy spin
Main Set: 30 min @ Zone 3 → 10 min @ Zone 4
Cool-Down: 15 min easy spin
8. Ten-Minute Threshold Repeats
Purpose: Accumulates thirty minutes at threshold through longer repetitions, with generous recoveries helping you prepare to sustain the effort again.
Warm-Up: 15 min easy spin
Main Set: 3 × 10 min @ Zone 4 (5 min easy spin between)
Cool-Down: 15 min easy spin
9. Threshold Climbing Repeats
Purpose: Gives you practice controlling threshold effort on a climb, adjusting your gearing as needed to keep the riding consistent through each repetition.
Warm-Up: 15 min easy spin
Main Set: 6 × 5 min climbing @ Zone 4 (5 min easy riding between, allowing longer if needed to descend safely)
Cool-Down: 15 min easy spin
10. Broken Threshold Blocks
Purpose: Splits each threshold block into a longer and shorter effort, using a brief recovery within the block before a longer reset between sets.
Warm-Up: 15 min easy spin
Main Set: 2 × (6 min @ Zone 4 → 1 min easy spin → 4 min @ Zone 4) (3 min easy spin between sets)
Cool-Down: 15 min easy spin
Separating Training Targets From Race Pacing
Completing a threshold workout can give you confidence in your cycling, but its interval targets serve a different purpose from your Ironman 70.3 race plan. Recovery breaks allow you to divide the harder riding into separate efforts. The event asks you to manage a continuous bike leg with a run still ahead, so completing a set of Zone 4 intervals does not establish the intensity you should hold throughout the race.
Keep that distinction in mind when a familiar workout begins to feel more manageable. You can recognise the improvement without immediately increasing every target or assuming your race pace should rise by the same amount. Consider how the threshold work sits alongside your longer rides and how well you recover from it. Together, those experiences give you a fuller understanding of your cycling than the strongest interval from one session.
Our How Does Threshold Work Support Ironman 70.3 Preparation? guide explores threshold training and the contribution it can make within your preparation for the distance.
Final Thoughts
There is something engaging about a ride where you know exactly what the next part asks of you. The start of an interval brings your attention back to the effort and its completion marks another piece of work done. That structure can make threshold cycling an enjoyable challenge within the months of preparing for an Ironman 70.3.
You do not need to leave every session with a higher number to feel pleased with the riding. Completing a workout with better judgement or finding a format you enjoy can make the time worthwhile. Let these sessions give you opportunities to experience that side of training and build confidence in the way you approach harder efforts on the bike.
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.
