Two Threshold Field Tests for Heart Rate and Power

More than just an audio Master Class, this audio recording and handout are a veritable continuing education workshop! Presented in this audio and pdf are two separate field tests; a twenty-minute test and an 8-minute version based on Chris Carmichael’s CTS field tests. Each version is applicable to both heart rate to estimate lactate threshold (LT) and to power, to determine functional threshold power (FTP). 

I provide you with a detailed explanation of each one as well as the differences between the two. You can determine which one you feel is more applicable to your own market and which one will be easier for your students to accomplish and to understand. Personally, I feel the twenty-minute one is easier to understand and administer, but it is more challenging for many students to accomplish. The eight-minute one is actually two sets of eight minutes, which is a bit more palatable to endure for many students. However, the explanation required and the conversion factor needed may (or may not) confuse your students a bit more.


  1. Jennifer, I think it might be better to take a higher percentage instead of ramping up, because that would just add more fatigue, perhaps lower the average HR by the end of the 8-min so you’ve negated the reason why you’re doing the 8-min test in the first place. Actually I am going to make a small change to this profile and announce it on ICA this week – it’s true that you need to take 90% of the power over 8-minutes…. but use 95% if it’s a HR test. Otherwise you end up with too low of a threshold. This takes into consideration a delay in HR rising.
    Using HR is so unreliable from person to person. A really fit person might be able to maintain 105% of their threshold easily for that 8-min (well, not “easy”, but better and more consistently than a non-fit person). A non-fit person might keep backing off and then surging, then backing off and then surging, and in reality, they might be actually only performing that 8-min at or near their threshold, so for them it would be more likely to be 100%. Hope this makes sense. My article (hopefully posted by tomorrow or Wed) will explain in more detail.

  2. Too boring. The first three minutes are torture!

  3. This information is so valuable, Jennifer. Thanks so much. WOW!

  4. I second to Renee : “WOW!”
    You are amazing as a MI and a giver ! You shared everything you know to inspire me to do the same for my riders.
    First I checked your 2 playlists, oh no don’t have those songs 🙁 Then when I saw the extra list, I now be able to compile a playlist from what I have! You covered everything and more… Now it’s time for me to make it happen–teach it! Hmmm? No excuses 😉
    Much appreciated, Jennifer.

  5. wow, thank you for the very generous offering. Renee

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