IRONMAN 70.3 · 18 Apr 2027
How to train for IRONMAN 70.3 Brasilia
Flat, flat and a lake. That is how the organiser sums up the race in the capital, and it is close enough to true that nobody questions it. The trouble is the word predominantly, which the organiser puts in front of flat on the bike and which covers twenty short rises spread across two laps of the city's wide avenues.
None of those rises decides anything alone. All of them together decide how you start the run, and a race in Brasília that has already run through five previous editions is won and lost on those three laps in the park.
By Kian Briel, founder. Analysed by engine 1, updated
What is actually on the road
The organiser's own course files, drawn the way the Event Analyzer draws a member's race.
- Swim1.9 kmDistance only
- Bike89.4 km in 2 laps639 m upCourse file
- Run21.2 km in 3 laps274 m upCourse file
The day starts in Lake Paranoá, one loop of 1.9 km in what the organiser calls calm waters. The only water temperature it has published is 24 C, from 2025.
Then 2 laps along the wide avenues of Brasília, past the landmarks of the capital, 89.4 km in all. Most of it is flat road, 87.9 percent of the whole course by distance. What the word flat hides is the pattern. Every few kilometres the road lifts for somewhere between 241 m and 432 m at 3 to 5.4 percent, then settles again. There are twenty of those rises across the two laps and 639 m of climbing between them. The steepest, 351 m at 5.4 percent, comes a little after the 8 km mark and again on the second lap.
The run is 3 laps inside a park, on flat paths surrounded by trees, 21.2 km in total. The profile agrees with the organiser. Its two longest segments, 29.5 and 19.4 percent of the leg, read dead level.
Course shape by distance
- Flat 88%
- Climbing 7%
- Descending 5%
The longest stretches
- Bike, climbing0.35 km1% of the bike
- Run, flat4.12 km19% of the run
- Run, flat6.27 km30% of the run
Each row is one unbroken stretch of the course that keeps the same shape the whole way. The number is how much of that leg you spend inside it, and it comes out the same whether you are fast or slow.
What this course asks of each leg
Twelve training dimensions scored for each leg against its own course, the way the Event Analyzer scores a member's race.
Aerobic endurance and muscular endurance lead every leg. On the bike they score 85 and 82. The run reads 85 and 83 for the same pair, the swim 85 and 80. Threshold capacity follows at 70 across the board. Because a Trained athlete spends more than half the day on the bike, the seven largest demands on the whole course are all bike demands.
The rises leave their mark in two scores. High-intensity capacity reads 58 on the bike against 42 on the run. Strength and force reads 45 on the bike. Neither is large. Both say the same thing: the bike keeps asking for a minute of work above your steady effort and then gives you flat road to recover on. Ask the engine to turn the bike file into a session and it produces a dozen one-minute efforts in Zone 5, each followed by a little over three minutes of easy riding. That is a fair portrait of an afternoon on these avenues.
Heat is present but not extreme. The organiser logged highs of 28 C, 27 C and 29 C over the last three editions, and environmental resilience scores 60 on every leg, in sixth place behind the endurance and threshold demands.
Now the bands. A Trained athlete swims 38:12, rides 3:04:21 at 182 W and runs 2:00:30, finishing in 5:53:03. The Competitive band comes home in 5:08:31, riding 2:43:05 at 249 W and running 1:42:23 from 4:20 /km threshold pace. Twenty-one minutes of that difference is bike and eighteen is run, and the run is the shorter leg.
- Aerobic endurance85
- Muscular endurance80
- Threshold capacity70
- Aerobic durability65
- Threshold durability65
- Environmental resilience60
- Fueling resilience55
- Technical skill55
- High-intensity capacity40
- Anaerobic capacity25
- Strength / force20
- Sprint power5
Nymiva reads what you can already show, from your own data
Connect your training history and the Focus Lab scores the same twelve dimensions this course demands against where you sit today. The gap between the two is what you train.
- MeasuredFrom your thresholds and testsThreshold power, threshold pace, critical swim speed and field tests you have done. The dimensions they can carry are scored directly.
- EstimatedFrom your training historyConnected activities are read for what they prove: long efforts, late-session fade, repeated hard work, fueling on long days. Each score says how it was read.
- ProxyFrom a stand-in, and named as oneWhere only an indirect signal exists, the score carries the proxy it came from and a lower confidence, never a number dressed as a measurement.
- UnmeasuredHonestly blankA dimension nothing in your data can answer stays unmeasured. It is never a zero, and the plan does not pretend to know it.
Every dimension ends in one word
- Develop the course asks more than you can show
- Maintain close enough to hold at the minimum dose
- Covered nothing to build here
- Unmeasured the course needs it, your data cannot say yet
Nymiva describes the course with twelve dimensions and the athlete with the same twelve. It reads the course side from the file on this page, and the athlete side from thresholds and connected training history, with a note on every score saying where it came from and how far it can be trusted. Where the course needs more than the athlete can show, there is a gap. Gaps are weighted by the share of the day they touch, so on this course a bike gap outweighs a swim gap of the same size by roughly five to one.
No athlete is behind this page. Its season therefore assumes the gaps fall where the demands are biggest and spreads 24 weeks over 5 developmental blocks and a two-week taper. The first block puts aerobic endurance in front in every sport. The second hands the bike and the run to threshold durability and the swim to aerobic durability. Threshold capacity leads all three sports in the third, muscular endurance in the fourth, and aerobic endurance comes back for the last block before the taper. Your own season is built from your numbers and will set different priorities.
Train the bike to protect the run
Which demands matter most across the whole race. A leg's demand counts for as much of the day as that leg takes, so a score of 85 on the bike outweighs the same score on the swim.
- 01Aerobic enduranceBike leg, 52% of the day85 × 52%44
- 02Muscular enduranceBike leg, 52% of the day82 × 52%43
- 03Threshold capacityBike leg, 52% of the day70 × 52%37
The bike takes 52% of the Trained reference band’s day, so its demands carry the most race weight. What the bike leaves in the legs is what the run gets.
Which demand gets a block, and when
The engine freezes one lead focus per sport on every developmental block, holds the rest at maintenance, and verifies before it reprioritises.
An illustration, not your plan. This page has none of your data, so the season below is the engine’s answer to one stated assumption: that your gaps line up with what IRONMAN 70.3 Brasilia demands. Your own season is built from your history, your thresholds, the days you can train and the races you have entered, and it will differ from this in its priorities, its sessions and its load.
- 01Run muscular endurance, a practice block4 weeks
- 02Run aerobic endurance, a development block4 weeks
- 03Bike muscular endurance, a practice block4 weeks
- 04Bike aerobic endurance, a development block4 weeks
In the order the allocator places them, general first, most race-like last.
- Week 1PrepPrep
A lead-in week. It develops nothing by design.
- Weeks 2 to 5Foundation 1Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportBike threshold durability
- SupportRun threshold durability
- SupportSwim aerobic durability
- Weeks 6 to 9Foundation 2Closes with a recovery week
- PriorityBike threshold durability
- PriorityRun threshold durability
- PrioritySwim aerobic durability
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- Weeks 10 to 13Foundation 3Closes with a recovery week
- PriorityBike threshold capacity
- PriorityRun threshold capacity
- PrioritySwim threshold capacity
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold durability
- SupportRun threshold durability
- SupportSwim aerobic durability
- Weeks 14 to 17Event shaping 1Closes with a recovery week
- PriorityBike muscular endurance
- PriorityRun muscular endurance
- PrioritySwim muscular endurance
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportBike threshold durability
- SupportRun threshold durability
- SupportSwim aerobic durability
- Weeks 18 to 21Event shaping 2Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportBike muscular endurance
- SupportRun muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportBike threshold durability
- SupportRun threshold durability
- SupportSwim aerobic durability
- Weeks 22 to 23PeakPeak
The taper. Load comes down toward the race, content stays specific.
- Week 24RaceRace
Race week.
Held at maintenance between blocks
- Runmuscular endurance, aerobic endurance, aerobic durability, threshold capacity, threshold durability
- Bikemuscular endurance, aerobic endurance, aerobic durability, threshold capacity, threshold durability
- Swimaerobic endurance, aerobic durability, threshold capacity, threshold durability, muscular endurance
Touches scheduled by each capability’s own decay, at a fraction of its development dose, so earlier work is still there on race day.
The sessions the blocks are built from
One entry per kind of work the block trains, at the intensity that work is meant to be done at. Where the same work runs at several lengths, the entry shows the span it grows across rather than one entry per length.
- Foundation 1 · Weeks 2 to 575 to 240 min
150 to 210 min at Zone 2
BikePower, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 540 to 270 min
180 to 210 min at Zone 3, then 30 min at Zone 4
BikePower, Zone 3Trains aerobic capacity - Foundation 1 · Weeks 2 to 535 to 120 min
90 min at Zone 2
RunPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 550 min
4 x 1.5 min at Zone 3, 6 min easy between
RunHeart rate, Zone 3Trains aerobic capacity - Foundation 1 · Weeks 2 to 545 to 51 min
4 x 8 min at Zone 2, 1 min easy between
SwimPace, Zone 2Trains aerobic capacity - Foundation 1 · Weeks 2 to 547 to 81 min
3 x 1000 m at Zone 3, 0.3 min easy between
SwimPace, Zone 3Trains aerobic capacity
12× rolling-course surges
1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, then 1 min at Zone 5, 3.3 min easy between
Compiled by the deterministic course compiler from the organiser’s file: the course’s one repeatable requirement, rehearsed at a dose the progression allows.
- Bike
- 73 min
- Trains threshold durability
- Supports muscular endurance
- Supports high intensity capacity
24 weeks, laid out backwards from race day
The shortest runway Nymiva builds for this event type, with its blocks, recovery weeks, taper and race week in place.
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- Prep
- Foundation
- Event shaping
- Peak
- Race
- Recovery week
Your own season carries these same phases on your own dates, with the load solved from your fitness and the days you can train, and it changes when your data does.
What each level does on the day
Reference finish times per peer band, the pacing plan the model holds each band to, and where the day is decided.
| Band | Swim | Bike | Run | Finish |
|---|---|---|---|---|
| Recreational2:11 /100m critical swim speed · 2.47 W/kg at 75 kg · 6:08 /km threshold pace | 0:45:05 | 3:20:07 | 2:24:54 | 6:40:06 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 0:38:12 | 3:04:21 | 2:00:30 | 5:53:03 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 0:33:03 | 2:43:05 | 1:42:23 | 5:08:31 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 0:29:36 | 2:28:57 | 1:30:34 | 4:39:07 |
Pacing plan
- 0 km1%26 km/h0:14
- 0.1 km-3.9%49.4 km/h0:13
- 0.28 km-0.3%32.3 km/h0:39
- 0.63 km3.4%16.8 km/h1:47
- 1.13 km-0.3%32.3 km/h7:35
- 5.21 km4.9%13.1 km/h1:53
- 5.62 km-0.1%31.3 km/h2:59
- 7.17 km3.3%17.1 km/h1:29
61 more segments in the full plan.
- Run: reach 4:20 /km and this course gives back 44:32.
Where it is decided
On the second bike lap, at the rises you have already seen once.
Lap one is honest. The legs are fresh, each rise is short, and holding 182 W up the 5.4 percent ramp feels like no effort at all. The steepest climb costs 1.1 percent of the bike leg. It is too short to lose time on and too short to gain any.
The cost arrives in bulk. Twenty rises are twenty invitations to go above your number, and a rider who accepts half of them on lap one reaches the same ramps on lap two with less to give and the same instinct to push. By then the average on the head unit still looks fine. The legs do not.
Then three laps in the park. Flat, lined with trees, and exactly the kind of run that rewards whoever arrived with something left. The longest level stretch holds 29.5 percent of the run leg, and on a warm day in Brasília that is where a well paced bike turns into minutes.
Getting it wrong
Believing the word flat. The riders who train only steady power on flat roads meet the first rise out of the lake and treat it as an event. It is not an event. It is one of twenty, and the right response to each is the same number you rode before it.
Swimming too hard in calm water. Lake Paranoá gives you no chop to fight, the field is fast, and a swim that feels easy can still take more out of you than the bike can afford.
Running the first lap to the crowd. A three-lap park course means you pass the same paths and the same supporters three times, and the first pass is the loudest. Run the opening lap at the pace you intend to hold on the third. Nobody on the final lap was ever grateful for a quick first one.
Conditions on the day
- 2026high 28 C, low 18 C
- 2025high 27 C, low 19 Cwater 24 C
- 2024high 29 C, low 19 C
From the organiser’s own records. Not a forecast.
Every session is a claim, every block is a test
A plan is not a calendar. Each key session states what it trains and how that is checked, and each block ends with a public verdict before the next one is chosen.
What a block promises
Bike aerobic endurance moves from your baseline to a stated target by the end of Foundation 1
- The baseline is your measured score when the block starts. The target is the score the model predicts for it.
- Verified at the block’s recovery week, by a field test or a refresh of the supply read from your history.
- Confidence rises by agreement between independent signals, never by one metric crossing a line.
- A block that misses its target is a public miss. The next block is chosen from what was proven, not from what was planned.
- 01Stimulus achievedThe work landed in the zone the session named, for the dose it named.
- 02Partially achievedSome of the work landed. The session banks what it can prove.
- 03Not achievedThe load may have been there. The stimulus was not, so nothing is banked.
- 04Data insufficientNo usable stream. The session is neither credited nor blamed.
- Session verified
- Progression banked
- Block verified
- Priority reassessed
- Plan adapted
Your numbers, this course
Analyze IRONMAN 70.3 Brasilia against my fitness
The same simulation and the same Focus Lab read, on your thresholds instead of a band’s. Three numbers give a finish estimate and a partial read. A connected history gives the whole table.
The first 14 days are free.
- Trained band finish
- 5:53:03
- Of the day on the bike
- 52%
- Dimensions scored per leg
- 12
- Season runway shown
- 24 wk
Questions people ask
- Is the IRONMAN 70.3 Brasilia bike course flat?
- The organiser calls it predominantly flat, and 87.9 percent of the whole course is flat by distance. The two bike laps still carry 639 m of climbing in twenty short rises, none longer than 432 m, and the steepest is 351 m at 5.4 percent.
- Where is the swim at IRONMAN 70.3 Brasilia?
- In Lake Paranoá, one loop of 1.9 km in water the organiser describes as calm. The only water temperature it publishes is 24 C, from 2025. The wetsuit decision is not on the course page, so check the athlete guide in race week.
- How many laps is the IRONMAN 70.3 Brasilia run?
- Three laps of 21.1 km in total, inside a park, on flat paths surrounded by trees. The bike is two laps on the wide avenues of Brasília.
- How hot is IRONMAN 70.3 Brasilia?
- The organiser logged highs of 28 C in 2026, 27 C in 2025 and 29 C in 2024, with lows of 18 C and 19 C. Warm rather than extreme, and most of that warmth falls on the run.
Course data from the organiser’s published files, analysed 24 Sept 2026 by engine 1, demand model 4. Reference times are simulated for a peer band at a stated reference athlete and are not a prediction for anyone. Nothing on this page is medical advice.
IRONMAN® and IRONMAN 70.3® are registered trademarks, and 5150 is a trademark, of World Triathlon Corporation. Nymiva is an independent training platform and is not affiliated with, sponsored by or endorsed by World Triathlon Corporation. Course data is read from the organiser’s public course pages for the purpose of describing the event.