Personally, if I get into a test week and I am feeling super blech that week, I’ll just run the 20 minutes in the zone it tells me to stay in (ie – zone 3) – at least that way, I know if I’m maintaining. Then usually every other test period ~ 8 weeks- I’ll do the full FTP test as listed under the intensity guidelines to see if it warrants a “bump” in threshold – not sure if that is a good way to approach it, but either way still ensures that I’m abiding by the intensity guidelines
Thank you for the replies. I ran the 20 min test during my 10 miler as prescribed in my plan then entered my average pace (from the 20 min) into my training peaks settings as my Threshold Pace. Do so recalculated all of my target paces.