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Connect Strava and Garmin and get the models coaches actually use — fitness and form, intensity distribution, aerobic decoupling, power curves and route comparisons. Then connect with the people you train with.
A Performance Management Chart built from heart-rate load, Foster monotony and strain, the Treff polarization index, and grade-adjusted decoupling. Every figure says how it was computed and where it stops being reliable.
Strava for the full history, Garmin for what only the watch knows — HRV, sleep, respiration, readiness, VO₂ max and per-second traces. Days recorded by both are counted once.
Connect with the people you ride and run with, compare efforts on routes you both know, and decide for yourself what each of them can see.