The Method.

FORGE isn't vibes. Every rule in the engine traces to published research or canonical coaching practice. Here's the whole recipe.

Periodization

Your plan works backward from race morning: Prep → Base (aerobic engine, 3 blocks) → Build (race-specific intensity, 2 blocks) → Peak (simulations) → Taper → Race. Load runs in 3:1 microcycles — three weeks progressive, one recovery week at ~55% volume, because adaptation happens in the absorb, not the dig. With a long runway, FORGE extends the base rather than inventing intensity: aerobic base is the Ironman currency.

Joe Friel, The Triathlete's Training Bible (5th ed.); Don Fink, Be Iron Fit

Intensity distribution

Roughly 80% of your training time sits below the first ventilatory threshold — conversational — with the remaining 20% split between race-specific tempo/threshold and small doses of speed. Long-course athletes trend pyramidal rather than strictly polarized: as the race approaches, the 'hard' 20% becomes Ironman-pace work inside long sessions, because specificity wins.

Stephen Seiler's training-intensity-distribution research; Fitzgerald & Warden, 80/20 Triathlon; Plews (EndureIQ)

Training load & form

Every session earns a Training Stress Score (TSS): power-based on the bike when available, pace-based for runs, CSS-speed-based for swims, heart-rate or session-RPE otherwise. Fitness (CTL) is your 42-day weighted average; Fatigue (ATL) the 7-day; Form (TSB) the gap between them. The plan aims you at race morning with TSB +15 or better — fit AND fresh (the bigger your CTL, the higher that number naturally lands). Sustained ramp rates are capped near +5 CTL/week because faster is where injury lives.

Coggan & Allen, Training and Racing with a Power Meter; TrainingPeaks PMC; Alan Couzens on ramp rates

The long sessions

Long rides cap at ~5.5 hours and long runs at 2.5 hours — beyond that, cost exceeds benefit and the next week suffers. You never run a training marathon: durability comes from frequency and consistency, not heroics. Bricks (run-off-the-bike) appear weekly from Base onward, growing from 15 minutes to race-pace simulations in Peak.

Endurance Nation (2.5h run cap); MyProCoach (ride caps); standard long-course brick progression

The taper

Two weeks out, volume drops ~40-60% on an exponential curve while intensity and frequency stay — that combination is the one shown by meta-analysis to maximize performance (~3% improvement, decisive over an Ironman day). Race week is openers, logistics, and carbs.

Bosquet, Montpetit, Arvisais & Mujika (2007), Med Sci Sports Exerc — meta-analysis of 27 taper studies; Mujika, Tapering and Peaking

Zones & testing

Bike zones come from FTP (95% of a 20-minute test), run zones from LTHR (average HR of the final 20 minutes of a 30-minute solo TT — Friel protocol) and threshold pace, swim zones from CSS ((400m time − 200m time)/2). Retest every ~8 weeks — the Ironman plan schedules the run TT for you; the bike and swim tests you slot in yourself. Imported Garmin history seeds honest starting estimates so you never train to stale numbers.

Friel LTHR protocol; Coggan power zones; Wakayoshi et al. (1992) CSS validation

Daily fueling

Macros are periodized to the work: carbohydrate scales from ~3.5 g/kg on rest days to 8-12 g/kg around monster days ('fuel for the work required'), protein holds at 1.8-2.0 g/kg spread through the day, fat floors at ~0.9 g/kg. The final 36-48 pre-race hours are a proper carb load — the scale goes up because you're storing race fuel.

Thomas, Erdman & Burke — ACSM Position Stand (2016); Burke, 'fuel for the work required'; 2025 Sports Medicine endurance-protein review

Race-day fueling

The gut is trainable and the plan trains it: every long ride from Build onward practices 80-100 g carbs/hour (glucose:fructose blends), because multiple transportable carbohydrates lift absorption beyond the old 60 g/h ceiling toward 90-120 g/h. Run legs target 60-80 g/h. Sodium 500-1000 mg/L of fluid, drink to conditions. Nothing new on race day — ever.

Asker Jeukendrup's multiple-transportable-carbohydrate research; Podlogar & Wallis (2022); current 90-120 g/h literature

Life happens (surf trips included)

Away weeks become maintenance blocks: easy beach runs, logged surf sessions, zero guilt. Unstructured sessions are scored with session-RPE (effort × minutes) so your fatigue model stays honest — surfing is real load (and decent paddling fitness), just not bike-run specificity. After any monster day (300+ TSS), FORGE inserts a recovery block and gates intensity for 5-7 days. The plan bends so it doesn't break.

Foster et al., session-RPE method (2001); CTS post-event recovery protocols; Matt Dixon, The Well-Built Triathlete (recovery as a pillar)

FORGE provides training guidance, not medical advice. See a physician before starting a program of this volume, especially with any cardiac history. Open water is never swum alone.