IRONMAN 70.3 · Aracaju · 29 Nov 2026
How to train for IRONMAN 70.3 Aracaju-Sergipe
The organiser sells this race as fast and flat, ideal for first-timers and personal bests alike. The file agrees with the flat part. The engine reads 99.6 percent of the course as flat by distance and does not find one climb on it. So people arrive on the coast of Sergipe with a personal-best plan they built in cooler weather.
What decides Aracaju is not on the profile. It is the air. The organiser logged a high of 30 C in 2025, 30 C in 2024 and 30 C in 2023, and the lows never fell below 25 C. On a course with nothing to climb, the heat is the hill.
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.
- Swim1.91 km2 m upCourse file
- Bike90 km in 3 laps300 m upCourse file
- Run21.2 km218 m upCourse file
The swim is one loop of 1.9 km in a river at Foz do Vaza Barris, with Orla do Pôr do Sol in view. The water was 28 C in 2025.
The bike is 3 laps of a mostly flat route, 90 km in all. The organiser describes Aracaju by its beaches, rivers and mangroves, and the profile reads the way that description sounds. Two short dips of about 200 m at a little over 3 percent, and otherwise nothing.
The run is 21.2 km along Atalaia Beach, laid out so spectators can follow the athletes closely.
Ask the engine where the time goes and the answer is almost blank. On the bike, one flat stretch from 5.5 km to 60.8 km holds 60 percent of the leg, and a second from 61 km to the line holds 32 percent. On the run, the first 13.4 km are a single flat segment and 63 percent of the leg. There are no landmarks in that reading. There is only effort, held or not held.
Course shape by distance
- Flat 100%
- Climbing 0%
- Descending 0%
The longest stretches
- Bike, flat55.3 km60% of the bike
- Bike, flat29 km32% of the bike
- Run, flat13.4 km63% 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.
Heat first. The demand model scores environmental resilience at 90 on every leg, and because the bike fills more than half of the day, the bike's 90 is the largest weighted demand on the course. The run's 90 sits seventh, above most of what the run's own profile asks.
Behind heat come the demands any flat half-distance triathlon makes. Aerobic endurance reads 85 on all three legs. Muscular endurance reads 81 on the bike, 83 on the run and 80 in the river. Threshold capacity sits at 70 everywhere. And then the scores fall away. High-intensity capacity reads 40 on every leg and strength and force reads 35 on the bike, because a course with no gradient never asks you to push hard against anything. Fueling resilience reads 55 on the bike and ranks tenth across the whole race, a demand of hours rather than of terrain.
The bands put times on it. A Trained athlete swims 38:23, rides 2:58:57 at 182 W and runs 1:59:58, for 5:47:18, with the bike 52 percent of the day. The Competitive band finishes in 5:03:26 from 4.15 W/kg at 75 kg and 4:20 /km threshold pace, about 21 minutes faster on the bike and 18 faster on the run. For the Trained athlete the run begins well over three and a half hours after the start, in air that has been at 30 C all day.
- Environmental resilience90
- Aerobic endurance85
- Muscular endurance80
- Threshold capacity70
- Technical skill69
- Aerobic durability65
- Threshold durability65
- Fueling resilience55
- 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 reads twelve dimensions twice. Once for the course, from the file and the organiser's conditions. Once for the athlete, from their thresholds and their connected training history, each score carrying a note on what it came from and how much to trust it. A dimension is a gap only where the course asks for more than the athlete can show, and gaps are weighed by how much of the day they fill. With the bike at more than half of a Trained athlete's day, a small bike gap outranks a larger swim gap.
This page has no athlete behind it, so its season cannot see anyone's gaps. It assumes they fall where the demands are largest and lays out 24 weeks in 5 developmental blocks with a two-week taper. Aerobic endurance leads the first block in all three sports. The second hands the swim to technical skill, the bike to aerobic durability and the run to threshold durability. Threshold capacity leads the third, muscular endurance the fourth, and aerobic endurance returns for the last block before the taper. A member's season starts from their own numbers and will disagree with this one.
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.
- 01Environmental resilienceBike leg, 52% of the day90 × 52%46
- 02Aerobic enduranceBike leg, 52% of the day85 × 52%44
- 03Muscular enduranceBike leg, 52% of the day81 × 52%42
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 Aracaju-Sergipe 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
- SupportRun muscular endurance
- SupportBike muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun threshold durability
- Weeks 6 to 9Foundation 2Closes with a recovery week
- PrioritySwim technical skill
- PriorityBike aerobic durability
- PriorityRun threshold durability
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportRun muscular endurance
- SupportBike 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
- SupportRun muscular endurance
- SupportBike muscular endurance
- SupportSwim muscular endurance
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun threshold durability
- Weeks 14 to 17Event shaping 1Closes with a recovery week
- PriorityRun muscular endurance
- PriorityBike muscular endurance
- PrioritySwim muscular endurance
- SupportBike aerobic endurance
- SupportRun aerobic endurance
- SupportSwim aerobic endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun threshold durability
- Weeks 18 to 21Event shaping 2Closes with a recovery week
- PriorityBike aerobic endurance
- PriorityRun aerobic endurance
- PrioritySwim aerobic endurance
- SupportRun muscular endurance
- SupportBike muscular endurance
- SupportSwim muscular endurance
- SupportBike threshold capacity
- SupportRun threshold capacity
- SupportSwim threshold capacity
- SupportSwim technical skill
- SupportBike aerobic durability
- SupportRun threshold 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, technical skill
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
Sustained course race pressure
60 min at Zone 4
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
- 85 min
- Trains threshold durability
- Supports aerobic durability
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 | 0:45:18 | 3:14:15 | 2:24:17 | 6:33:50 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 0:38:23 | 2:58:57 | 1:59:58 | 5:47:18 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 0:33:12 | 2:38:18 | 1:41:56 | 5:03:26 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 0:29:45 | 2:24:35 | 1:30:11 | 4:34:31 |
Pacing plan
- 0 km0.2%29.8 km/h10:46
- 5.35 km-3.1%45.8 km/h0:15
- 5.55 km0%30.8 km/h1:47:38
- 60.8 km-3.4%47.2 km/h0:16
- 61 km0%30.8 km/h56:28
- Run: reach 4:20 /km and this course gives back 43:52.
Where it is decided
On Atalaia Beach. But the result is settled on the long flat middle of the bike.
That stretch from 5.5 km to 60.8 km is 60 percent of the leg with nothing in it to change your effort. No climb to slow you, no descent to recover on, and three laps to remind you how the last one went. Ask the engine for a session built from this file and it returns one unbroken hour in Zone 4 between a warm-up and a short cool-down, with no intervals at all. That is the leg exactly. A single number, held for most of three hours, in heat.
The Trained band holds 182 W for 2:58:57 and then runs 1:59:58. A rider who spent the first lap above that number does not lose the time on the bike. They lose it on the first 13.4 km of the run, which is 63 percent of the leg as one flat segment, where the pace they planned in a cooler place meets 30 C and gives way. The Competitive band's 18 minutes on the run are not found on the run. They belong to a rider who holds a higher number just as evenly, and still has legs for the beach.
Getting it wrong
Believing the brochure. Fast and flat is true, and it is exactly what makes riders race the first lap like a time trial at home. There is no terrain to meter the effort against, so the only brake is the number you decided on before the start. Decide it for 30 C, not for spring.
Treating the river as a warm-up. The water was 28 C in 2025. It feels gentle, and it is the first 38:23 of a Trained athlete's day spent in heat. Swim it at the effort you planned rather than the one the warm water suggests.
Running to the crowd. The run is set up so spectators can follow you closely along Atalaia Beach, and they will cheer the first kilometres as loudly as the last. The first 13.4 km are one flat segment and most of the leg. Pace them for the heat you are in, and let the beach carry you home at the end instead of the start.
Conditions on the day
- 2025high 30 C, low 26 Cwater 28 C
- 2024high 30 C, low 26 C
- 2023high 30 C, low 25 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 Aracaju-Sergipe 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
- 5:47:18
- 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 Aracaju-Sergipe course flat?
- Yes. The organiser describes three laps of a mostly flat bike route and a flat run along Atalaia Beach. The engine reads 99.6 percent of the whole course as flat by distance and finds no climb on it at all. The 300 m the bike file registers is spread across 90 km in rises too small to count as climbs.
- How hot is IRONMAN 70.3 Aracaju-Sergipe?
- The organiser logged a high of 30 C in each of 2023, 2024 and 2025, with lows of 25 C to 26 C. The river was 28 C in 2025. Heat is the largest single demand on this course, ahead of anything the profile asks for.
- Where is the swim at IRONMAN 70.3 Aracaju-Sergipe?
- In a river at Foz do Vaza Barris, one loop with a view of Orla do Pôr do Sol. The organiser does not publish the wetsuit rule on its course page, so check the athlete guide in race week.
- How long is the season on this page?
- The illustrative season runs 24 weeks, with five developmental blocks and a two-week taper. It is built from the course alone. A member's season starts from their own numbers and can be longer.
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.