Letters to the Coaches: When and How to Test Zones | 80/20 Endurance

Letters to the Coaches: When and How to Test Zones

Dear David W,

I’m going to buy your plan for the level 3 half marathon plan. I have a race (in Madrid, Spain) on April 8 which by my calculations will have me starting Dec 31/Jan 1… I had a bike wreck in a triathlon a few months ago that resulted in broken bones, concussion, etc. So I’m just now starting to get back into where I can work out 4-5 times a week. So I’m on pace to be at least to the proper starting place for your program.

I am a gadget guy. I supported Stryd on Kickstarter and upgraded to the footpad at the first opportunities. I record my power on my runs, but it is just another interesting bit of data that I review at the end of some of my runs. So I’ve never really done much with it. That is why I’m so intrigued by this [the 80/20 power-based run plans].

So that leads me to my questions: When should I do the power test? I would assume fairly close to the start of the program so that my numbers are pretty accurate for that time. As my training increases and my thresholds change, will I be doing more tests during the training plan?


Dear DH,

I wish you the best of luck on your recovery.

You are exactly right, particularly where you are coming back from low fitness, your power thresholds will constantly change (improve). The run plans have RT (run tempo) workouts scheduled every recovery week, which is every 3rd or 4th week. Those RT workouts are designed to confirm or re-establish your zones. Therefore, you’ll be testing regularly anyway with an 80/20 plan.

It would be good to do a test before your start your regular training. We have a suite of tests in our Intensity Guidelines for Running document on our 80/20 Resources page. Some of the tests are brutal (30-minute time trial) and some are easier, if slightly less accurate. I would do the easy test at first. Make sure to see the section on RT workouts at the bottom of that guide.

Also consider that HR zones will change very little. Your output for a given HR will, but early on, consider using HR as a secondary (or primary) measure of intensity until your power zones level off.

Finally, we offer a Level Guarantee. If you buy the Level 1 plan and find that 8 weeks later it is too easy, come back to me and I’ll get you the L2 plan for free. This applies to leveling up or down on all of our plans.


Matt and I periodically publish anonymously your inquiries to us, particularly when the answer may benefit the community. Have a question about 80/20 training or training in general? Feel free to e-mail me. David W.