Ironman Distance Brick Session: 120km Bike + 10km Run

Session Overview

This session is your closest race-preparation brick for a full-distance Ironman. 120km at controlled Ironman bike power — around two-thirds of the full race bike leg — followed immediately by a 10km run off the bike at target Ironman run pace. The goal is not to exhaust yourself; it’s to rehearse the physiological and mental transition between sustained cycling and running on fatigued legs, and to test your nutrition strategy over a meaningful race-representative duration.

What You’ll Need

• Triathlon or road bike (race-fit position if possible)
• Power meter and GPS watch or bike computer
• Race nutrition: gels, bars, or real food equivalent to what you plan on race day — one intake every 20–25 minutes
• Two water bottles minimum; electrolytes for hot conditions
• Running shoes accessible in T2 (transition practice optional but recommended)

Warm-Up (15–20 minutes)

Begin the ride easy for the first 15–20 minutes. Build gradually from Zone 1 to Zone 2, then into your Ironman target power zone. Do not spike effort or sprint early — this session rewards controlled pacing across the full duration. The first 20km is your warm-up whether you treat it as one or not.

Main Set

• Bike: 120km total — Hold 65–70% FTP (Normalised Power) throughout. Target Variability Index (NP÷AP) of 1.05 or below on flat terrain, 1.06–1.08 on hilly routes. Never go above 80% FTP on short climbs. This is sustained-effort territory, not threshold.
• Nutrition: every 20–25 minutes — Practice exactly what you plan to eat on race day. For a typical 120km at Ironman pace you should consume 4–6 nutrition intakes of 150–300 calories each. Do not skip feeds even if you feel fine — you are practising a protocol, not just surviving a session.
• Run: 10km immediately off the bike — Target Ironman marathon pace (not faster). Your legs will feel different in the first kilometre than they do in the third; pace by effort and GPS, not by how the first 500m feels. Aim for negative split or even pace — not a fast start.

Cool-Down (10 minutes)

Walk 5 minutes after finishing the run before stopping completely. Eat real food within 30 minutes: carbohydrates and protein (rice and chicken, recovery smoothie, or similar). Elevate legs if possible. This brick creates meaningful training stress — the recovery protocol after it is as important as the session itself.

Coaching Notes

• Schedule this session 10–14 days before your A-race at the latest; do not attempt it in the final week before a full Ironman
• If your power drops significantly in the final 30km of the bike, you went out too hard or under-fuelled — adjust nutrition strategy before race day
• The first kilometre off the bike will feel strange regardless of fitness level; this is normal and temporary — settle into your run after 1.5–2km
• To make it easier: reduce to 90km bike + 8km run. To make it harder: add race-course specific terrain (climbs matching your A-race profile) and aim for 140km bike + 12km run if your peak training week allows