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Power vs HR TSS

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    • #20631
      AvatarBrad H

      What’s the best way to handle variations in plan when alternating between Power and HR for a given workout?

      Recently I noticed that when I toggle a LWC plan workout in Training Peaks from Power-based to HR-based, the TSS changes by almost 25% (downward). This for a 90min Z2 ride. TP staff tell me this because HR TSS is calculated differently (and for a range), but how should I manage that with training? I mean a guy can only afford so many power meters, and it’s kind of nice to mix-up training across bikes/terrains. Should I just increase intensity of HR based ride to match TSS of the originally planned Power ride?

      This is still a bit confusing to me if my threshold heart rate is my heart rate (approximately) when I tested for threshold power… because Z2 power and Z2 heart rate are both ranges.


    • #20634

      Hi Brad,

      TSS (training stress score) metric is produced by power data.

      TSS = IF x IF x duration in hours x 100. Takes into account both
      the intensity (i.e., IF) and the duration of each training

      IF – Intensity Factor

      IF = Pn/FTP. The ratio of the normalized power to your threshold power.

      It is an accurate data produced metric.

      Power and HR do not track in a linear manner. HR is influenced by caffeine, heat, fatigue, altitude, humidity, time of day, cadence, fitness, health, drugs, adrenaline and more. TSS based on HR is not an accurate metric to base your training on.

      When using HR to pace your training sessions I recommend following HR zones and guidelines in the descriptions to nail your workouts rather than using TSS. TSS is a valuable metric for pacing with power but not HR.

      Coach Lynda

    • #20636
      AvatarBrad H

      Hi Lynda,
      That’s helpful.
      Thank you!

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