Ironman 70.3 · 1.9 km / 90 km / 21.1 km
Your race is on the calendar.
Now the training has a shape.
SeLo turns your race date, your current numbers, and the hours you actually have into a periodised 70.3 plan — every session with personalised pace, power, and heart-rate targets, from your first Base week to race morning.
Free while in beta · No credit card · Not medical advice
One season · four phases · load that rises, absorbs, and sharpens
How it works
From questionnaire to race morning
01
Tell us where you are
A short onboarding covers your race date, swim, bike, and run background, known numbers like FTP or recent race times, and the weekly hours you can honestly commit.
02
We build the season
SeLo estimates your thresholds from what you know, derives your five training zones per sport, and lays out Base, Build, Peak, and Taper around your race — deload weeks included.
03
Train, log, sharpen
Every session shows exact targets in your zones. Log what you did, retest along the way, and your zones, targets, and race predictions tighten automatically.
The method
Coaching science, computed for you
Nothing exotic — the same periodisation, zone anchoring, and load management a good coach would apply, made rigorous and personal.
Thresholds, not guesswork
Zones are anchored to your lactate threshold heart rate, FTP, threshold run pace, and Critical Swim Speed — estimated on day one from proven formulas, then replaced by your own field-test results.
80/20 polarised training
Roughly four-fifths of your week sits at genuinely easy intensity so the remaining fifth can be properly hard. It's how endurance athletes at every level absorb more training with less breakdown.
Progressive overload, capped
Weekly volume never jumps more than ~10%. Every third or fourth week deloads so the work you did actually turns into fitness — the dips you can see in the arc above.
A plan that answers back
Fitness (CTL), fatigue (ATL), and form (TSB) are computed from every session you log, alongside a race-time prediction that sharpens as the data comes in.
Under the hood
Tanaka max-HR estimation · Karvonen heart-rate reserve · CSS from 400/200 time trials · Riegel race-time scaling · FTP from 20-minute or ramp tests · training load as TSS with a power → pace → heart rate → RPE fallback ladder · CTL/ATL/TSB performance management. Every number in your plan traces back to one of these.
Features
Everything between sign-up and the finish chute
Week-by-week calendar
Your whole season at a glance — phases, deloads, long sessions, bricks, and the race itself.
Personal zones, every sport
Five zones for run HR, bike HR or power, run pace, and swim pace — recalculated whenever your thresholds change.
Session targets that mean you
Not "ride moderately" — 148–160 bpm, 172–190 W, 5:35–5:55 /km, 2:02–2:05 /100 m. Your numbers.
Field-test driven
Built-in FTP, 30-minute run, and CSS test protocols. Log a result and every future session rescales.
Fitness, fatigue, form
A performance-management chart shows fitness building and fatigue clearing — so the taper makes visible sense.
HR-only friendly
No power meter? Every ride still gets precise heart-rate targets, and watt targets appear the day you add one.
Swim-developing path
Can't swim 200 m continuously yet? The plan starts with technique-and-interval progressions until you can.
Race-day plan
Predicted splits, pacing bands, and a fuelling plan in grams and millilitres per hour — practised before it matters.
Life-proof regeneration
Race moved, hours changed? Regenerate the remaining season in one click without losing your history.
Athletes
Built with the first-timer in mind
SeLo is in beta. These placeholder cards will be replaced with real athlete stories — no invented endorsements.
“I knew how to swim, bike, and run. I had no idea how to put them together for twenty weeks. SeLo did the thinking; I did the training.”
First-time finisher (placeholder)
Testimonials will appear here once our beta cohort crosses their finish lines.
“The deload weeks felt wrong until I saw my form line climb right before race day. Trust the arc.”
Beta athlete (placeholder)
Real athlete stories coming soon.
“No power meter, no problem — every ride had heart-rate targets that made sense, and my plan updated the day I finally bought one.”
Beta athlete (placeholder)
Real athlete stories coming soon.
Pricing
Free while in beta
Final pricing is not set. Everything below is a placeholder for what we're considering — beta athletes keep full access either way.
Beta
$0
Everything, free, right now.
- Full plan generation & athlete portal
- Field tests, zones, and progress charts
- Race-day pacing & fuelling plan
Later · placeholder
TBD
A simple monthly plan once we leave beta.
- Everything in beta
- Multi-race seasons
- Device & platform integrations
FAQ
Fair questions
I've never done a triathlon. Is this for me?
Yes — SeLo is built around the first-time 70.3 athlete. The onboarding meets you where you are, including a swim-developing track if you can't yet swim continuously, and the plan respects a hard weekly-hours ceiling you set.
How long do I need before race day?
The generator accepts 8 to 104 weeks and will periodise whatever runway you give it. Most first-timers do well with 16–24 weeks of consistent training; with more than ~28 weeks, SeLo adds a preparation block before the race-specific build.
Do I need a power meter or fancy watch?
No. A heart-rate monitor is strongly recommended, but every workout carries heart-rate and pace targets. If you have (or later add) a power meter, watt targets appear automatically.
What if I don't have a race booked?
Choose a rolling 12–52-week block instead of a race date. The structure is the same; you can attach a race and regenerate whenever you commit.
What happens when I get faster?
Log the built-in field tests (FTP, 30-minute run, swim CSS). Your thresholds update, your five zones per sport recalculate, and the targets on every remaining session rescale — the plan keeps pace with you.
Is this medical advice?
No. SeLo provides general training guidance and includes a PAR-Q-style health screen before you start. It is not a medical service; consult a physician before beginning any exercise program, especially if the screen flags anything.
The start line is set. Start the arc.
Ten minutes of questions. A full season of structured, personalised training.
Build my plan