Calculate your Training Stress Score. Project your fitness, fatigue, and form over 14 days.
Enter 14 values separated by commas. Use 0 for rest days.
TSS (Training Stress Score) quantifies how hard a workout was relative to your threshold. A 1-hour ride at FTP = 100 TSS. The formula is TSS = duration_h x IF^2 x 100, where IF (Intensity Factor) = NP/FTP.
CTL (Chronic Training Load) is a 42-day rolling average of TSS, representing your fitness. ATL (Acute Training Load) is a 7-day rolling average, representing fatigue. TSB (Training Stress Balance) = CTL - ATL, representing your form or freshness.
This model was developed by Dr Andrew Coggan and Hunter Allen, building on Banister's impulse-response model.
Sources: Coggan/Allen formulas, Banister TRIMP model
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