[Christian]

Hi @pvoosen, thanks for your reply! It helps me too to think things through and understand these concepts precisely.

• I decided to write 5 bpm instead of 5% because 5 bpm of 95 bpm is 5.26% and 5 bpm of 100 is 5.00% … so the percentage value changes as you move the slope triangle along the line although the slope is the same. I wanted to refer to the bare slope without messing about with percentages.
• You may be right and TrainingPeaks does not adjust for duration. It was just a guess and after seing your research on the topic I would take my assumption back.
• But I completely agree with you, some compenstation for duration should be performed! An activity that produces 5% fatigue in one minute is definitely of different intensity than an activity that produces 5% fatigue over two hours. So to my mind only fatigue per duration can serve as a reasonable indicator for threshold intensity.