Duathlon Brick Session: Run-Bike-Run Race Simulation

Session Overview

This duathlon brick session replicates the run-bike-run race format to build race-specific fitness and sharpen your T1 and T2 transitions. Targeting intermediate athletes with a 90-minute total duration, it’s an essential session in the weeks before a duathlon race and equally valuable as a general multisport fitness workout during the spring race build.

What You’ll Need

• Road bike or turbo trainer (outdoor recommended for this session)
• Cycling shoes and helmet
• Running shoes (set up in transition before starting)
• GPS watch
• Water bottles on the bike and in transition
• A short transition area — a towel near your bike rack point

Warm-Up (10 minutes)

Start with an easy 2km jog at RPE 4 to raise your running body temperature. Follow immediately with 5 minutes of easy bike spinning (if starting on the bike in your A/B race, reverse this order). This brief warm-up primes both disciplines without leaving you fatigued for the main set.

Main Set (70 minutes)

Set up your transition area before starting. Arrange your bike kit and run kit for a fast change at each discipline swap.

• Run 1: 5km at sprint-to-Olympic duathlon pace (RPE 7). This is strong but not all-out — aim for roughly your 10km race pace. The temptation to go too hard on Run 1 is the most common duathlon mistake. Note your exact split.
• T1: Rack your run shoes, put on helmet and cycling shoes. Practice efficiency — every second here is free time. Target 45–90 seconds for T1.
• Bike: 20km at time trial effort (RPE 7–8). Aim for a consistent power output rather than surging and recovering. Eat and drink on the bike — even for a 20km effort, fuelling ahead of Run 2 makes a measurable difference.
• T2: Rack the bike, swap to running shoes, remove helmet. Target under 60 seconds.
• Run 2: 2.5km — the goal is to match Run 1 pace. This is harder than it sounds. Your quads will be heavy, your breathing will be laboured from the bike, and your legs need 400–600m to find their running rhythm. The athletes who execute Run 2 well are the ones who resisted the temptation to overcook the bike.

Cool-Down (10 minutes)

Easy 5-minute jog followed by walking. Stretch hip flexors, quads, and calves — these are the muscles most stressed by the run-bike-run sequence. If time allows, a gentle 5-minute spin on the turbo is an excellent active recovery addition.

Coaching Notes

• The single most important pacing lesson in duathlon: go out slower than you think you should on Run 1. It feels counterintuitive on race day, but athletes who start at 90–92% rather than 98% consistently outperform on Run 2.
• During T1, always put your helmet on before touching the bike. This is a DQ rule at sanctioned events — build the habit in training so it’s automatic in races.
• On Run 2, focus on running form in the first kilometre rather than pace. High cadence and relaxed shoulders help your legs adapt faster from the cycling position to an upright running gait.
• Do this session 2–3 times in the six weeks before a target duathlon race, progressively extending Run 1 or the bike distance to build race-specific endurance.