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IRONMAN 70.3: 16 weeks, peaks at ~15 h.

1.9 km swim, 90 km bike, 21.1 km run in 4–8½ h: a capped-IF bike that protects the half marathon, and fuelling on the clock. That's the intermediate plan; beginner runs 18, advanced runs 16 weeks.

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Written for where you are.

Beginner
18 weeks: the long ride 90 → 210 min, the long run 50 → 100 min, a long-course brick every two weeks and gut training from week 10.Shortest runway 12 weeks · research minimum 14 · 10 sources
18 wk
5-12 h a week
Intermediate
16 weeks: a long-course brick every week from week 5, alternating race-pace and easy runs, a 90 km race-pace ride in week 11 and a full-swim simulation in week 14.Shortest runway 10 weeks · research minimum 12 · 10 sources
16 wk
7-15 h a week
Advanced
16 weeks: four swims with Red Mist as the second key swim, two quality rides, a 4:30 long ride with 3 × 30 min at race power, and a race simulation in week 11.Shortest runway 9 weeks · research minimum 10 · 10 sources
16 wk
10-19 h a week

The checklist comes with it.

T-7Course recon: the bike turns and the swim exit.
T-3Bike check: tyres, gears, brakes. Race belt and number, elastic laces.
T-2Wetsuit decision from the water temperature: USAT makes it mandatory below 16 °C, allowed up to 78 °F, and 78.1–83.9 °F without award eligibility.
T-1Photograph your transition layout. Gels are optional.
race morningArrive 90 min early; a 10-min swim warm-up, then a seeded or rolling start.
T-3Bike fuelling plan, bottles pre-mixed; a pacing card with your watts and run pace.
T-3A sighting-landmark list for the swim course.
T-1Chafe protection for a longer wetsuit swim.
T-7No new products from here on. Check the cut-offs.
T-3Bike nutrition laid out by the hour; an IF / TSS pacing card; a sunscreen and heat plan; the special-needs bag if offered.
T-2Carbohydrate-focused eating for the last 24–36 h.

Every plan cites its homework.

Amateur medians come from secondary summaries of race databases. The run bands add a 4–6% off-the-bike allowance that is coaching consensus, not measured, and the IF-by-split-time targets are practitioner-derived (Ashburn), not trial-validated. No RCT has tested brick training itself.

  1. 1Helios research dossier — triathlon, duathlon and aquabike events
  2. 2Wikipedia — Ironman 70.3
  3. 3Marathon Handbook — average half Ironman times (RunTri / Voyage data)
  4. 470.3 performance predictors — systematic review 2026 (PMC13379040)
  5. 5Best Bike Split — pacing the 70.3 bike leg: IF and TSS
  6. 6Jeukendrup 2014 — carbohydrate intake during exercise (PMC4008807)
  7. 7Costa et al. 2017 — gut training (PubMed 28177715)
  8. 8Martinez et al. 2023 — gut training systematic review (PMC10185635)
  9. 9Hew-Butler et al. 2006 — sodium supplementation RCT at Ironman (PMC2492002)
  10. 10Speedy et al. 2000 — hyponatraemia at NZ Ironman (PubMed 10695851)
  11. 11Knechtle et al. 2026 — swimming-induced pulmonary oedema review (PMC13424964)
  12. 12Wells et al. 2026 — objective training load in age-group triathletes (PMC13171522)

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