Build phase : specific capacity development
LoadTraining block after aerobic base, focused on threshold and race-specific intensities.
The Build phase follows the Base phase in classic Friel periodization. Its goal is to increase intensity specific to the target race : more threshold work (Z4), VO2max intervals (Z5), and race-pace simulations. Typical duration is 8-12 weeks before taper. It is the most demanding phase: volume remains high AND intensity increases. It ends with a recovery week before entering the Peak or Taper phase. For Ironman, Build includes long sessions at IM race pace (85-90% of race tempo).
In TriPaced:
In TriPaced, the Build phase appears in the plan timeline between Base and Peak. Zone 4 sessions progressively increase (controlled ramp rate) and long bike sessions include blocks at IM intensity. The planner guarantees no Build week exceeds physiological ramp rate limits.