Brick Session: 40km Bike and 5km Run

Session Overview

This classic 40km bike followed by a 5km run brick session is the cornerstone of Olympic and 70.3 triathlon preparation. You will train your legs to transition from cycling to running efficiently, practising the specific physical and mental demands of race day.

What You’ll Need

Warm-Up (10 minutes)

Begin the bike leg with 10 minutes of easy riding at Zone 2, gradually building effort. Complete 3 short accelerations of 15 seconds each in the final 3 minutes to open the legs before the main effort begins.

Main Set

Complete the full brick with a fast transition between disciplines. Aim to keep T2 under 90 seconds in training to simulate race conditions.

  • Bike — 40km at race pace effort (RPE 7/10, Zone 3-4): maintain steady power output, avoid spiking effort on climbs
  • Take on 1 gel at 15km and 1 gel at 30km to practise race-day fuelling
  • T2: rack bike, swap shoes, apply number belt, go — target under 90 seconds
  • Run — 5km at race pace (RPE 7.5-8/10): expect jelly legs for the first 1km — this is normal and will pass
  • Hold target run pace from km 2 onwards; finish strong through the final kilometre

Cool-Down (5 minutes)

Walk for 2 minutes after crossing your finish line, then light jogging for 3 minutes to bring your heart rate down gradually. Stretch your quads, hip flexors, and calves — these take the most strain during the bike-to-run transition.

Coaching Notes

  • Do not go too hard on the bike — it is tempting, but leaving something in the tank makes the run achievable
  • The heavy leg sensation in the first kilometre of the run is normal; pace yourself conservatively until it passes
  • Advanced option: add a second 5km run rep after 10 minutes rest to build run volume
  • Target total session time: approximately 1 hour 45 minutes to 2 hours including transition

Training at your own risk. The information provided is for general guidance only and is not a substitute for professional medical advice. Please consult a doctor before starting any new exercise programme, especially if you have any pre-existing health conditions.