Let users configure their training zones — HR, power, and pace. Manual entry, auto-calculate from physiological anchors, or sync from providers.

Updated for SYNTHESIS schema (expanded scope)

This is now broader than just HR zones. The SYNTHESIS training_zones table supports:

Zone types

• Heart rate zones: percentage of max HR or lactate threshold HR
• Power zones: percentage of FTP or absolute watt ranges (Coggan levels)
• Pace zones: percentage of threshold pace or absolute s/km ranges

Zone versioning (GoldenCheetah pattern)

• effective_from date on each zone set — insert new rows, don't overwrite
• Historical activities resolve to the zones that were active at the time
• Example: max HR test on March 15 shows 185 → new zone set from that date, old zones preserved

Both absolute and percentage-based

• Absolute: coach sets specific values, or synced from Garmin/TrainingPeaks
• Percentage: standard zone systems (Coggan, Karvonen, Friel) — resolves to absolute using nearest athlete_metrics anchor value (FTP, max HR, etc.)

Per-sport overrides

• sport_type = NULL = default zones for all sports
• sport_type = 'cycling' = cycling-specific power zones
• Running gets HR + pace zones, cycling gets power + HR zones

Zone priority per sport (sport_zone_priorities)

• Which metric drives time-in-zone display: power > HR > pace for cycling, HR > pace for running
• Which metric drives training load calculation
• Default equipment auto-assignment per sport

TRIMP weighting

• Each HR zone carries a weighting factor for HR-based training load calculation
• e.g., Z1 = 1.0, Z2 = 1.1, ..., Z5 = 4.0

Depends on

• #31 Implement SYNTHESIS Schema
• #35 Training Zones & Zone Analysis Schema

Blocks

#21, #24, #25

Reference

See docs/api-research/SYNTHESIS.md §7 (training_zones table, sport_zone_priorities table).