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80/20 plan with power zones

chrisdr2
over 7 years ago
About a month ago I started a level 2 80/20 plan based on HR zones. Since Garmin introduced running power, I decided to change the plan zones to use power. I did a running FTP test based on a protocol from runwithpower.com and fed the resulting value into Matt Fitzgerald's 80/20 power zone calculator.

So far, the zones above 1 seem to match well with the HR zones that I was using previously. However, I found it impossible to keep within Z1. I suspect that slow running increases VO causing the algorithm to report higher power values. My activity on GC does indicate that VO
increased during the Z1 interval. Not sure whether this is an issue with the algorithm overcompensating for VO, or just how it works.

For anyone interested, here is a link to the activity: https://connect.garmin.com/modern/activity/2388235914

The first 5 min split is supposed to be Z1, but average power was into Z2. The other splits are Z2, until the last - I gave up on Z1 and did a fast walk to cool down.

Z1: 183-276
Z2: 277-320

  • 0 over 7 years ago
    I'm not familiar with Fitzgerald's zones specifically, but I do note that many people have reported that Garmin's running power numbers are substantially higher (by 100 watts or so) than those produced by other devices eg. Stryd.

    As running power is a mathematical estimate rather than a direct measurement (as with cycling power meters), who knows which is correct? (both sets of numbers have an impressive list of academic references).

    But with Garmin's numbers being so new, it may be that Fitzgerald's zones are using the lower numbers. Which would account for a Garmin zone 1 being so hard to achive
  • 0 over 7 years ago
    Yes, it is early days with these numbers. It could be that zone 1 is low, but the other zones do match up consistently with the HR zones that I had set. Perhaps my running efficiency goes to hell at that pace :-)

  • 0 over 7 years ago
    You have done the FTP Test with Garmin Running Power and take % of this value. So it is of no interest how it differs from Stryd. I think the zones from Fitzgerald are much to low. Jim Vance takes 80% to 88% for Z1. With the values from Fitzgerald i walk along with a hr of 80-90bpm for Z1.
  • 0 over 7 years ago
    That's what I've decided to do also. With a quick walk, I can get within sight of Z1 of the HR plan.