Use Percentage of FTP or cTHR for staying in Zone 2?

Training
#1

Hi All,

I started riding again a few months ago after a decades long break. I’ve done a few ramp tests using the Systm platform on a smart trainer, and finally did one after getting a HR monitor. Systm calls the test the ‘Half Monty’.

That test estimates your cTHR (cycling Threshold Heart Rate) based on your heart rate during the ramp test, and of course it estimates your FTP.

The ramp test determined my cTHR is 165bpm (I’m 50 y/o). Systm says my Zone 2 HR is 70-87% of the cTHR, or 116-144 bpm.

My FTP is 218w. (For those not familiar with that particular FTP test, following the ramp test there is a 20 min ‘constrained’ effort where you must keep your heart rate in a certain range, which has been determined based on what your HR during the ramp portion. Your FTP is calculated based on both the ramp portion and how much power you produced in the 20 minutes while keeping your HR in the given range.)

Due to some changes with goals and training philosophy, I’m going to move to a more 80/20 style of training.

So, to stay in Zone 2 (and maybe be biased toward the upper range of Zone 2, is it better to use HR or the power meter?

Followup question: I swim, run, use the stairmaster, etc based on travel schedule and where I can squeeze in a session. For example, work gym has the treadmills and stairmaster. I faintly recall that LTHR can be different across different modalities. Should I need to do another test to find my Zone 2 running heart rate?

Many thanks.

#2

You are asking some training philosophy questions, and different camps will answer differently. Important to experiment in my opinion. That said my cycling LTHR tested on 40-70 minute time trial efforts has been around 160bpm for six years. I’m ten years older. I’ve been using Friel HR zones, for z2 that’s something like 128-142bpm. I do a lot of 60-150 minute zone2 rides by power. When looking at HR, it’s usually starts around 134bpm and slowly ramps up to 140bpm. Power target of 180W at beginning and I slowly push up to 200W during ride (ftp of 270).

Just one perspective. Hope that helps.

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#3

I agree with windwarrior about different philosophies, but I think his advice is a great starting point (and maybe even best long term…you will need to determine that).

I’m saying this as someone who doesn’t like using fixed %FTP for endurance or tempo, but I came to that conclusion later and for reasons that would not help you. Right now, be consistent, and do all the things you’re supposed to do to improve.

Having said what I said above, you should do this. Different modalities, different total muscle mass usage (basically), different HR. Running will likely be higher.

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