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CoachingCOMPARISON

BASE PHASE VS BUILD PHASE

QUICK VERDICT

Most amateurs leave base too early. A proper base phase delivers adaptations you cannot rush — mitochondrial density, fat oxidation, aerobic enzyme concentration — and a short base leaves build work sitting on sand. Switch to build when you can hold a conversation in Zone 2 for 90+ minutes and your 30-day aerobic decoupling stays below 5%.

SIDE BY SIDE

FEATUREBASE PHASEBUILD PHASE
Intensity distribution80-90% Zone 2, minimal intensity60-70% Zone 2, 20-30% threshold + VO2max
Primary adaptationAerobic system, mitochondria, capillary densityLactate clearance, FTP, VO2max ceiling
Typical duration6-12 weeks (longer for less-trained riders)6-8 weeks
Weekly hours (amateur)8-15 hours (volume is the point)6-12 hours
Fatigue accumulationLow — recovers quickly between sessionsHigh — needs structured recovery
Strength trainingHeavy, 2x weekly — compatible with easy aerobicMaintenance only, usually 1x weekly
Readiness signalAlways appropriate as starting pointAerobic decoupling <5%, effortless Zone 2 for 90+ min

CHOOSE BASE PHASE IF

  • ✓Cyclists in the off-season (October-February for most riders)
  • ✓Riders returning from a break or injury
  • ✓Anyone whose easy rides don't feel easy
  • ✓Masters cyclists for whom base work delivers disproportionate gains

CHOOSE BUILD PHASE IF

  • ✓Cyclists 8-12 weeks out from an A-race or target event
  • ✓Riders whose base has been solid for 2+ months
  • ✓Returning structured athletes who already have an aerobic foundation
  • ✓Riders whose goal event requires high-intensity performance

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