Brick : the bike-run combo
RunA bike session immediately followed by a run, no break.
A brick simulates race-day T2 transition feel: heavy legs, cadence reset, pacing under post-bike load. It prepares you physically and mentally for what would catch you mid-race otherwise. Typical IM build volume: 4-5h Z2 bike + 30-45 min Z2 run.
In TriPaced:
TriPaced auto-places 1-2 bricks per build block on Saturdays or Sundays depending on your availability. The brick's run leg is capped to avoid stacking too much impact on already-loaded legs.
Source Friel J., The Triathlete's Training Bible (4th ed., 2016) - brick protocol for IM build