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    Build Phase Training Guide

    Build phase

    Build Phase One-Pager

    Aerobic base turns into race-specific fitness here. One sheet, four sessions, no guesswork.

    The rules

    1. Volume plateaus or drops slightly. Intensity climbs. Do not raise both at once.
    2. Sessions get race-specific: race-pace intervals, open water, bricks.
    3. Strength shifts from foundational to power-focused.
    4. Nutrition and pacing get rehearsed in the long sessions, not invented on race day.

    Build length and volume by distance

    Race distanceBuild lengthWeekly hours
    Sprint3–4 weeks5–7 hours
    Olympic4–6 weeks7–10 hours
    Half Ironman6–8 weeks10–14 hours
    Full Ironman8–12 weeks12–18 hours

    Keep / drop

    Keep

    • One long session per sport per week
    • Two brick workouts a week
    • Zone 2 on the easy days, genuinely easy
    • Race-nutrition rehearsal on every long session
    • A recovery week roughly every fourth week

    Drop

    • Adding intensity on top of unchanged volume
    • Hard days back to back
    • Testing new gear in key sessions
    • Junk-mile middle intensity that is neither easy nor hard
    • Foundational strength volume. It is power work now

    The session menu

    Threshold intervals
    2 × 20 minutes at threshold (comfortably hard) with 5 minutes easy between. Builds lactate clearance.
    Tempo effort
    30–60 minutes at hard-but-sustainable, roughly 10 km race pace. Raises sustainable race pace.
    Brick workout
    Bike straight into a run, twice a week. The single most triathlon-specific session there is.
    Race-pace long session
    Long ride or run with the middle portion held at goal race pace. Teaches pacing and builds confidence.

    Red flags

    • Resting heart rate climbing week on week, or sleep going backwards.
    • Race-pace efforts getting slower rather than more repeatable.
    • You skipped the recovery week because you felt fine. Take it anyway.
    • Every session is moderately hard. Polarise it: easy days easy, hard days hard.

    Next step

    Build sessions are where race fuelling gets rehearsed. Set your targets before the next long ride.

    Race Nutrition Planner

    Condensed from the full Build Phase Training Guide. mytriathloncalculator.com

    Get the other phase one-pagers

    Base, build, peak and taper: the printable sheets, plus the calculators as they ship.

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