SIDE BY SIDE
| FEATURE | BASE PHASE | BUILD PHASE |
|---|---|---|
| Intensity distribution | 80-90% Zone 2, minimal intensity | 60-70% Zone 2, 20-30% threshold + VO2max |
| Primary adaptation | Aerobic system, mitochondria, capillary density | Lactate clearance, FTP, VO2max ceiling |
| Typical duration | 6-12 weeks (longer for less-trained riders) | 6-8 weeks |
| Weekly hours (amateur) | 8-15 hours (volume is the point) | 6-12 hours |
| Fatigue accumulation | Low — recovers quickly between sessions | High — needs structured recovery |
| Strength training | Heavy, 2x weekly — compatible with easy aerobic | Maintenance only, usually 1x weekly |
| Readiness signal | Always appropriate as starting point | Aerobic decoupling <5%, effortless Zone 2 for 90+ min |