Training Plan Triathlon 70.3: The Complete Method

The 70.3 triathlon (1.9 km swim, 90 km bike, 21.1 km run) is a demanding milestone: it requires endurance, effort management and structured preparation over several months. Here's the method to prepare for it smoothly.

How long to prepare a 70.3?

For an athlete who already has an endurance base (3-4 sessions/week for a few months), expect 16 to 24 weeks of specific preparation. New to long distance triathlon? Aim for 6 months instead to build the foundation progressively and limit injury risk.

Periodization: Build then Taper

An effective plan is organized in successive phases (approach inspired by Joe Friel):

• Base (6-10 weeks): volume in fundamental endurance, swimming technique, bike strength. You're building the engine.
• Build (6-8 weeks): add specific intensity (threshold, race pace), bricks (bike + run back-to-back), and increase long session volume.
• Taper (10-14 days): reduce volume (~40-50%) while keeping some intensity, to arrive fresh on race day.

Every 3 weeks or so, include a recovery week (reduced volume) to absorb the load and progress without breaking down.

Swim / Bike / Run Distribution

On 70.3, the bike represents the largest share of race time: typical distribution is around 20% swim, 45% bike, 30% run, 5% strength. The bike is where you gain (or lose) the most time — don't neglect it.

Key Sessions Each Week

• 1 long bike session in endurance (progressive build-up to 3h+).
• 1 bike quality session (threshold/tempo) for sustainable power.
• 1 long run, sometimes as a brick (right after the bike) to get legs used to it.
• 2 swim sessions (technique + endurance/race pace).
• The rest in easy endurance (zone 1-2).

Mistake #1: Too Much Intensity

Most amateurs train too hard, too often. Research (Stephen Seiler) shows that performing endurance athletes spend ~80% of their volume at easy pace and only ~20% at intensity. Running/cycling "moderately hard" all the time fatigues without driving progress. Learn more about 80/20 polarization.

Managing Race Day

Start easier than planned on the bike: that's the classic trap. Eat and drink regularly from the start (your body doesn't absorb well when effort increases). See our triathlon nutrition guide.

A Plan Truly Tailored to YOUR Data

A generic plan doesn't account for your form of the day, fatigue, how you feel or the weather. That's exactly what a coach does: adapt continuously. Sports Coach AI generates your 70.3 plan each week based on your actual data (Garmin, Strava, Intervals.icu), and adjusts it based on your load and recovery.