Triathlon Brick Training Calculator

A brick workout is a training session combining two triathlon disciplines back-to-back, most commonly bike followed immediately by run. The term “brick” likely comes from the heavy, leaden feeling in the legs during the run portion — as if they are made of bricks.

Brick training serves two purposes:

1. Physiological adaptation: Training the muscles to switch from the cycling movement pattern (quadriceps-dominant, circular) to running (hamstring and glute activation, linear). This adaptation takes weeks to develop and is sport-specific — running fitness alone does not prepare you for running off the bike.
2. Mental practice: Learning to manage the uncomfortable transition period and pace yourself before your legs “come around” (usually after 1–2 km).

Target paces for brick sessions:

• Bike pace: 75–85% of race bike effort. Slightly below race pace to preserve running legs.
• Run pace: First kilometre: 15–20 seconds/km slower than race run pace. After 1–2 km, aim to gradually reach race pace.

Brick session structures by race distance:

• Sprint prep: 30 min bike + 15 min run, 2× per week in the last 4 weeks
• Olympic prep: 60 min bike + 20 min run, 1–2× per week in last 6 weeks
• 70.3 prep: 90–120 min bike + 30–45 min run, 1× per week
• Ironman prep: 3–4 hr bike + 45–60 min run, 1× per week in peak training

The first brick: Expect the run to feel terrible the first few times — this is normal and will improve quickly. Focus on smooth turnover rather than pace for the first few sessions.