The bike-to-run brick: why, how, how often
The bike-to-run brick is the most triathlon-specific session: running right after the bike. It's what prepares legs for T2, teaches the brain to manage the very particular feeling of the first 2 km of run after the bike, and locks in pacing on race day. Here's the playbook.
What a brick actually does
Many triathletes think a brick is about "getting the legs used to it". Partly true, but the main game is neuromuscular and mental: learning to run with different mechanics, managing the heavy-legs feeling in km 1-2, and rehearsing run pacing after the bike effort.
A brick isn't disguised endurance. On Sprint and Olympic, the run after bike is at target race pace, not low endurance. On 70.3 and Ironman, it sits at half or marathon pace.
Typical brick structure
An effective brick runs 15 minutes (Sprint) to 60 minutes (Ironman) of running after the bike. The bike segment must be realistic: race pace, not an easy long ride.
- Sprint: 1h bike at race pace + 15-20 min run at race pace
- Olympic: 1h30 bike at race pace + 25-30 min run at race pace
- 70.3: 2h30 bike at 70.3 pace + 30-40 min run at half pace
- Ironman: 4-5h bike at Ironman pace + 30-60 min run at marathon pace
How often?
1 brick per week in the specific phase for Sprint and Olympic. 1 brick of 2-3h every 10 days for 70.3. 1 long simulation brick every 15 days for Ironman, 4-6h bike + 30-60 min run.
In the base phase, the brick is rare or absent: you build bike and run separately. It appears in build and becomes central in specific.
Mistakes to avoid
Mistake #1: brick too slow. If you run at jog pace after your bike, you learn nothing about race pacing. Mistake #2: change clothes, eat a meal and leave 30 minutes later. Real transitions last 1-2 minutes, not 30.
Mistake #3: chaining bricks too often. A brick is very tiring. More than one per week is overload.
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