70.3 Race Simulation Brick: 90km Bike + 15km Run

Session Overview

This full 70.3 race simulation brick — 90km at race power followed immediately by a 15km run — is the definitive race-prep session for any Ironman 70.3 competitor. Scheduled 3–4 weeks before your target race, it tests your pacing strategy, nutrition execution, and the physical and mental demands of the bike-to-run transition at race intensity. It’s one of the most demanding sessions in triathlon training, and the most race-specific you’ll do.

What You’ll Need

• Road or triathlon bike in race condition — check brakes, gears, and tyre pressure before leaving
• Running shoes and kit ready for an immediate T2 transition at your turnaround point
• Full race nutrition and hydration: target 60–90g carbohydrate per hour on the bike
• GPS watch with multisport or manual lap function
• Support vehicle or pre-arranged feed station for water and extra nutrition on longer efforts

Warm-Up (10 minutes on the bike)

Start with 10 minutes of easy Zone 2 cycling, gradually increasing cadence to your race cadence (88–92 rpm). Avoid any hard efforts in the warm-up — this is a long session and you need every joule for the main set. Take your first nutrition (gel or bar) within the first 15 minutes to front-load your fuelling.

Main Set

• Bike: 90km at 70.3 race power (85–90% FTP) — Hold steady power through rolling terrain, resisting the temptation to spike on climbs. This is your actual race power, not your training power ceiling. Fuel every 20 minutes without exception — missing a feed is a race-wrecking mistake you can rehearse away from here.
• Run: 15km at 70.3 goal half-marathon pace — Begin immediately off the bike. The first 2–3km will feel heavy and awkward — this is completely normal and resolves as your legs adapt. Hold your goal race pace from kilometre 3 onward. Don’t panic and slow down unnecessarily in the early km.
• Negative split target — Aim to run the second 7.5km fractionally faster than the first. This mirrors the optimal 70.3 half marathon strategy and trains the mental discipline to hold back early.

Cool-Down (10 minutes)

Walk 5 minutes at the finish, then gentle stretching of quads, hip flexors, and calves. Start recovery nutrition within 30 minutes — aim for a 3:1 carbohydrate-to-protein ratio. This session will leave you genuinely fatigued; plan a rest day or very easy active recovery the following day.

Coaching Notes

• Schedule this session 3–4 weeks before race day, not in the final two weeks. You need adequate recovery time to absorb the training stimulus before taper begins.
• Use your exact race nutrition: same brands, amounts, and timing as you plan on race day. This is your final rehearsal.
• If your power or pace falls significantly in the second half, your planned race pacing is too aggressive — recalibrate before race day.
• Easier variation: 75km bike + 10km run if you’re building toward your first 70.3 or targeting a conservative race strategy.