IRONMAN 70.3 · Erkner · 12 Sept 2027
How to train for IRONMAN 70.3 Erkner
On paper, Erkner is the easy one. The organiser calls it fast and flat, a course for first-timers and personal bests alike, and the file does not argue. Across 111 km it climbs 205 m, and the engine cannot find a single stretch steep enough to call a climb.
Flat is not easy. Flat means the course never makes a decision for you. There is no hill to slow you down and no descent to hand time back, only 2 laps of straight road beside the river Spree and 4 laps through town. A Trained athlete spends 50 percent of a 5:41:43 day on that bike, and the race turns on one number chosen early in the first lap.
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.
- Swim1.93 kmDistance only
- Bike88.1 km in 2 laps131 m upCourse file
- Run21.3 km in 4 laps74 m upCourse file
The swim is 1 lap of the Dämeritzsee from the Strandbad Erkner, 1.9 km in a lake that lies half in Berlin city territory and half in Brandenburg. The organiser describes flat wooded banks and clean, clear water, and logged it at 19 C in 2025 and 17 C a year earlier. From the water exit it is roughly 150 m to the bike park at the sports centre in Erkner, which serves as both transitions and sits near the finish line.
The bike leaves on straight, newly paved roads along the Spree and heads out into the Oder-Spree region before coming back round for its second lap. The organiser's file measures 88.1 km for both laps together, with 131 m of climbing. The run is 4 laps through Erkner itself, past the marketplace and the Gerhart-Hauptmann-Museum, a memorial to the poet who won the Nobel Prize for Literature. It measures 21.3 km and climbs 74 m.
Read the profile and there is nothing to read. The engine looks for climbs and descents and finds neither. It cuts the bike into a single flat segment carrying 99.8 percent of the leg, and the run into one flat segment carrying all of it. Two segments for a whole half-distance triathlon.
Course shape by distance
- Flat 100%
- Climbing 0%
- Descending 0%
The longest stretches
- Bike, flat88.1 km100% of the bike
- Run, flat21.3 km100% 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 first, muscular endurance a step behind, and very little else. The demand model scores aerobic endurance at 85 on all three legs. Muscular endurance reads 80 on the bike and in the swim, 81 on the run. Threshold capacity sits at 70 on every leg. Because the bike fills half of a Trained day, the five largest demands on the whole course belong to it once the scores are weighted by time.
What the course leaves out tells you as much. Strength and force reads 35 on the bike. High-intensity capacity is 40 everywhere, sprint power 15. Technical skill on the bike comes in at 39, which is what straight new tarmac produces. Give the engine this bike file and ask it for one session, and it returns the plainest workout in its vocabulary, an 85-minute ride built around one hour of unbroken Zone 4. The reason is simple. On a road this even, held output counts for more than surges.
For the Trained reference athlete the day reads 38:50 in the lake, 2:52:07 on the bike at 182 W, 2:00:46 on foot, 5:41:43 in all. The pacing plan for that ride is one row long. It holds 30.8 km/h at 182 W from the first metre to the last, because nowhere on the course gives the engine a reason to change it. The Competitive band finishes in 4:58:27 from 4.15 W/kg at 75 kg. It rides 2:32:15 at 249 W and runs 1:42:37, and none of that gap is bought in one place. There is no one place.
Fueling resilience reads 55 on the bike and the run. A day of 5:41:43 on steady effort is long enough for that demand to matter. Weather is mild by comparison. The organiser's highs run from 17 C in 2024 to 22 C in 2026, and environmental resilience scores 10 on every leg. The number worth noting is the low of 8 C in 2024, on a September morning that begins in a lake.
- Aerobic endurance85
- Muscular endurance80
- Threshold capacity70
- Aerobic durability65
- Threshold durability65
- Fueling resilience55
- Technical skill55
- High-intensity capacity40
- Anaerobic capacity25
- Strength / force20
- Environmental resilience10
- 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 from the course file and the same twelve from the athlete, taken from their thresholds and connected training history, each score carrying a note on where it came from and how far to trust it. A gap only exists where the course asks for more than the athlete can show. Gaps are then weighted by how much of race day they fill, so on this course a bike gap outweighs a swim gap of the same size by a wide margin.
This page knows nothing about you. Its season assumes the simplest case, that your gaps sit where the demands are highest, and lays out 24 weeks in 5 developmental blocks before a two-week taper. Aerobic endurance leads the first block in all three sports. Aerobic durability leads the second, threshold capacity the third, muscular endurance the fourth. Then aerobic endurance comes back for the fifth. A member's season is drawn from their own numbers and will not look like 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.
- 01Aerobic enduranceBike leg, 50% of the day85 × 50%43
- 02Muscular enduranceBike leg, 50% of the day80 × 50%40
- 03Threshold capacityBike leg, 50% of the day70 × 50%35
The bike takes 50% 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 Erkner 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 aerobic durability
- SupportRun aerobic durability
- SupportSwim aerobic durability
- Weeks 6 to 9Foundation 2Closes with a recovery week
- PriorityBike aerobic durability
- PriorityRun aerobic 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 aerobic durability
- SupportRun aerobic 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 aerobic durability
- SupportRun aerobic 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 aerobic durability
- SupportRun aerobic 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
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 | 0:45:50 | 3:06:49 | 2:25:14 | 6:27:53 |
| Trained1:51 /100m critical swim speed · 3.03 W/kg at 75 kg · 5:06 /km threshold pace | 0:38:50 | 2:52:07 | 2:00:46 | 5:41:43 |
| Competitive1:36 /100m critical swim speed · 4.15 W/kg at 75 kg · 4:20 /km threshold pace | 0:33:35 | 2:32:15 | 1:42:37 | 4:58:27 |
| Elite1:26 /100m critical swim speed · 5.27 W/kg at 75 kg · 3:50 /km threshold pace | 0:30:05 | 2:19:03 | 1:30:46 | 4:29:54 |
Pacing plan
- 0 km0%30.8 km/h2:51:40
- Run: reach 4:20 /km and this course gives back 43:16.
Where it is decided
In the first lap of the bike.
On a hilly course the terrain meters your effort. Go too hard and the next climb tells you. Erkner has no next climb. The first lap along the Spree comes with fresh legs, a full field and a road that never tilts, and every number feels sustainable. A rider who drifts above 182 W for that lap will not feel it on the second. They will feel it on the run.
That run is 4 laps of the same flat loop, and the engine reads it for aerobic endurance and muscular endurance above everything else. A Trained runner needs 2:00:46 from an input of 5:06 /km threshold pace. The laps make the damage easy to see. Every pass of the marketplace is a split to set against the last one, and the rider who overspent early watches each one come back slower.
Getting it wrong
The first mistake is letting the day choose your power. Straight roads and a flat file make a higher number feel free, and the number you settle on in the opening hour is the one your run inherits.
The second is the swim. The water in the Dämeritzsee is clean and clear, the banks are flat and wooded, and a fast swim invites a harder one than planned. It is then 150 m on foot to the bike park and 88.1 km of riding that charges interest on whatever was spent.
The third is the town. Four laps through Erkner mean four passes of the marketplace and the Gerhart-Hauptmann-Museum, with the spectator support the organiser promises lining the route. Runners answer that noise with pace on the first lap. The fourth lap is where they pay for it.
Conditions on the day
- 2026high 22 C, low 11 C
- 2025high 21 C, low 12 Cwater 19 C
- 2024high 17 C, low 8 Cwater 17 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 Erkner 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
- 5:41:43
- Of the day on the bike
- 50%
- Dimensions scored per leg
- 12
- Season runway shown
- 24 wk
Questions people ask
- How flat is the IRONMAN 70.3 Erkner bike course?
- As flat as a course gets. The organiser describes two laps on straight, newly paved roads along the river Spree, and its file measures 88.1 km with 131 m of climbing. The engine finds no climb and no descent anywhere on it and reads the bike as one flat segment.
- Where is the swim at IRONMAN 70.3 Erkner, and how warm is the water?
- One loop of the Dämeritzsee from the Strandbad Erkner, a lake that lies half in Berlin city territory and half in Brandenburg. The organiser logged the water at 19 C in 2025 and 17 C in 2024, with no reading for 2026. The wetsuit decision is not on the course page, so check it in race week.
- How many laps is the IRONMAN 70.3 Erkner run?
- Four laps through Erkner, past the marketplace and the Gerhart-Hauptmann-Museum. The organiser's file measures 21.3 km with 74 m of climbing, and the engine reads the whole leg as one flat segment.
- How long is the season on this page?
- Twenty-four weeks, with five developmental blocks and a two-week taper before race week. It is drawn from the course alone. A member's own season starts from their numbers and can run 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.