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POWER & PERFORMANCE
Training Stress Score
Calculator v1.0
Calculate your Training Stress Score (TSS) from normalised power, FTP, and ride duration.
Use the reference tables to gauge recovery demand and plan weekly training load.
Methodology
IF = Normalised Power ÷ FTP
TSS = (Duration in seconds × NP × IF) ÷ (FTP × 3600) × 100
Training Stress Score was developed by Dr Andrew Coggan as a way to quantify the physiological
cost of a workout relative to your current fitness (FTP). An IF of 1.0 means you rode at your
threshold; a one-hour ride at exactly FTP yields a TSS of 100.
Changelog:
v1.0 — Initial release. Training Stress Score calculator from duration, normalised power, and FTP with recovery and weekly load guidance.