Duathlon Long Distance Build Plan 12 Weeks is a 12-week triathlon plan. This article combines the actual plan description with a example week from the stored workout entries.
What this plan is built for
This 12-week Build Plan builds on the Base Plan. The goal is still to increase your VO2max, essentially making the engine bigger. However, these intervals will be longer and combined with Sweetspot and KA3 intervals towards the end of the block to counteract a high lactate production rate, especially on the bike. The training remains very "polarized", meaning that the easy sessions should be truly relaxed, and the hard sessions should be correspondingly intense. It is still important, especially during the high-intensity VO2max sessions, that you perform them realistically, meaning not too intensely. Keep an eye on your heart rate; it should not be significantly above your threshold HR at the end of the intervals (5-8 BPM is okay). Also, ensure adequate carbohydrate intake before and during these high-intensity sessions.
During running, the long run is now supplemented with "faster" segments in the upper Base Zone. This serves as a foundation in combination with tempo strength, without costing too much substance.
Important: Not every day is the same - on a stressful day, it may well be that you need to adjust the intensity downwards during the session. That is perfectly okay and happens even to world-class athletes. The goal is always to complete the session "as best as possible". So, it’s better to do three blocks with reduced intensity than two blocks and then stop.
Training logic and load
The build phase adds more specific stress while keeping enough easy work to preserve quality week after week. The important part is not upgrading easy days into hidden hard days. The workout data shows which sessions are structured and which ones are intentionally simple.
The plan contains 130 scheduled entries across 12 weeks. The sequence matters as much as the total hours: hard, technical, or long workouts only work when the surrounding days allow you to absorb them.
Example week: Week 4
This week is not a generic template. It is built from the actual training plan entries, and the workout charts use the stored workout data.
Ramp from 50% to 75% | 10 min @ 60% | 12 min @ 75% | 10 min @ 60% + 3 more steps
LIT Training. Time: 1h10 (18 min @Fatmax included) HR: approx. 60-70% of HRmax. Perceived exertion: 4-5 out of 10 Cadence target: 85 to 95 rpm Effect: Mitochondrial biogenesis, muscle fiber shift, improvement in fat metabolism LIT is not the same as Fatmax.
Perform a 30-minute athletic / stability training session. Typical exercises may include: - Lunges - Squats - Superman - Push-ups - Leg raises - Plank - Side plank - etc.
60 min @ 75% | 8x 0 min on / 1 min easy
The goal is to optimize fat metabolism and to perfect running technique in a fatigued state with the strides at the end.
Ramp from 50% to 75% | 3 min @ 60% | 3 min @ 75% | 3 min @ 80% + 17 more steps
HIT Decrease Training: 5 x (1 min at 125% / 3 min at 108% of FTP) Perceived exertion: approx.
80 min @ 60%
Training goal: Base endurance sessions make up the largest part of triathlon training.
15 min @ 70% | 5x 1 min on / 2 min easy | 5 min @ 70% | 5x 1 min on / 2 min easy + 3 more steps
The goal of the hill runs is to improve your sub-distance performance and enhance anaerobic capacity.
Perform a 30-minute athletic / stability training session. Typical exercises may include: - Lunges - Squats - Superman - Push-ups - Leg raises - Plank - Side plank - etc.
40 min @ 70% | 6x 0 min on / 1 min easy
The goal is to prepare you for tomorrow's race. The intensity of the run should be more relaxed than intense.
Ramp from 50% to 75% | 3 min @ 60% | 3 min @ 75% | 3 min @ 80% + 4 more steps
MIT - SweetSpot Training: 3x10 min @85% FTP; Cadence = 55 rpm (5 min rest) Perceived exertion: 6-7 out of 10 Effect: Improvement of metabolic efficiency, enhancement of lactate transport, and potential increase in fractional utilization.
80 min @ 75% | 20 min @ 94% | 10 min @ 97% | 10 min @ 65%
Primarily a calm base run that becomes progressive towards the end. This run primarily serves to optimize fat metabolism, as well as to develop pace endurance towards the end.
2 h @ 60%
LIT Training. Rate of Perceived Exertion: 3-4 out of 10 Effect: Mitochondrial biogenesis, improved local oxygen extraction, and an increase in fat metabolism.
How to read the workout charts
The chart is based on the workout data: longer segments take more width, higher intensities sit higher, and harder work is marked with stronger colors. For swim or distance-based segments, the graphic represents the planned sequence rather than GPS data.
Practical execution
What to watch
- Execute the key days precisely instead of making the easy sessions faster.
- Use the plan description as context: equipment, fueling, mobility, and realistic threshold values are part of the training.
- When life or fatigue adds pressure, trim secondary work first and keep the most important session stable.
Training effect
Executed well, the plan improves your ability to absorb the intended stimulus repeatedly. Depending on sport and phase, that means more aerobic stability, better pace durability, stronger technique under fatigue, or more confidence at target effort.