What TSS Measures

Training Stress Score converts a workout's duration and intensity into one number. Because it uses Normalized Power, interval sessions — which cost more physiologically than steady rides at the same average power — score higher. One hundred TSS points approximates an hour at threshold effort.

Using TSS in Training

Track weekly TSS to manage load: under 150 is recovery, 150–300 builds base, 300–450 is a strong build week, and 450+ is peak volume. Increase weekly load gradually (10–15% max) and schedule recovery weeks every third or fourth week.

Limitations

TSS assumes your FTP is accurate — test it regularly (20–60 minute efforts). It also models cycling-specific stress; running and strength training add load that TSS does not capture, so combine metrics when training across disciplines.