Two Random Training Questions - FTP vs. running; endurance zone

Hi Everyone :slight_smile: Got two random questions I’m curious about if you have thoughts:

  1. Any of you who do running and cycling have a sense of what race distance the cycling FTP/20 minute might be equivalent to? I know that the answer might be ‘however hard you can run for 20 minutes’, in which case I might say 2 mile to 5k+ depending on one’s capacity. Mainly I’m trying to remember how different races felt when I used to race a loooooong time ago, so I can get a better sense of how workouts will feel. Basically my perceived effort meter needs a little refinement I think.

  2. For base training, I heard a recommendation (good youtuber cyclist) recently to aim to stay in zone 2 for long rides. I’m not doing base training yet, but going to plan for it, and also I’m just curious about longer rides in general. Now I don’t know if this person means the traditional heart rate zone 2 or based off of LTHR like SF.

Thanks for any thoughts!

  1. don’t know I’ve only been running just over a year and do all my running in Z2.
  2. I use the Sufferfest calculation for HR zones, which I know work for me because I can do long outdoor rides fasted if I stay in Z2 for HR. For me a traditional 70% of Max HR for a Z2 ceiling is way to easy.

I noticed a big difference in how much harder the hard intervals were and how easier the easy intervals were when I switched from RPE to virtual power. Having a metric to compare to RPE helped reset my internal RPE scale.

The perceived effort scale in this article is pretty spot on

Heart Rate: Everything You Ever Wanted to Know but Were Afraid to Ask – The Sufferfest

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Well I’ve not done much running in decades, and never had a heart monitor when I did. But I’ve done long endurance rides where you need to pace properly to finish.

Regarding the 20 minute/FTP zones, the SF FTP being done in a fatigued state is closer to what I could hold for an hour of steady state effort. I kind of proved that to myself, anecdotally, by riding up Alpe de Huez on FullGaz last year, where I held my FTP for 1.5 hours (I was due for a retest) and the retest bumped my ftp up about 10 watts.

That said, there’s also Time To Exhaustion (TTE) which basically tracks with your power curve (at least as I understand it) assuming you are doing maximal efforts at various intervals frequently to keep the curve fresh.

As far as running goes, I’d assume it’s similar but with a lower FTP since you are moving more that just your legs. I’d be interested to see what others have to say as well. I’m considering cross-training a bit more and may incorporate running if my joints can tolerate it.

Great questions and I hope I’ve helped a bit.

EDIT: a final thought on Z2 riding or endurance rides in general, although I have a power meter, I don’t generally use it for pacing. I don’t monitor my heart rate either. I generally use my breathing and resistance to gauge my pacing. If I’m breathing hard or pushing too hard on the pedals I need to back off. Going too easy isn’t generally even a consideration since I’m only riding easy when I’m doing a recovery ride.

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I’ve been running since high school. Got out of it for a while, but have been back at it for the last 15-20 years.

One thing that helped me is The McMillan pace calculator (I think that’s what it’s called) which works off of a “magic mile” pacing system.

Do your normal pre-run routine / stretches.
Run 1 mile warm up.
Run 1 mile flat out as fast as you can. This is your “magic mile” time
Run 1 mile recovery.

The calculator then adjusts your times to predict your expected race times at different distances as well as training paces to use in your workouts.

What I found worked for me was similarly to do a “magic mile” as well as a “magic 5k”. Once I had these times and efforts done I could use RPE to figure out how fast to do my runs when I chose not to run with a watch (or even when I did so I didn’t need to keep checking it).

I then would do my workouts based on my expected pace for a specific race distance.

Z1 = marathon pace or slower
Z2 = half marathon pace
Z3 = 10k pace
Z4 = 5k pace
Z5 = 1 mile pace
Z6 = sprint

So if I was training for a 5k: I would do tempo workouts at 10k pace and recovery at marathon pace. If I did interval workouts I would do 400/800m intervals at 1 mile pace with half marathon pace recovery in between.

I do make some small RPE adjustments based on experience, but this helps me get my workouts paced correctly without having to put in too much thought. And every few months you either need to do new “magic miles” and/or adjust your goal time(s).


Thanks everyone for the responses! Super helpful. @JGreengrass Thanks for sharing the bit about hard intervals feeling harder and easy intervals feeling easier. I’ve noticed that this week in my workouts, so helps me validate I’m in the right ballpark.

Something interesting I noticed relative to my question here, in the SF chart on this page, I see that power zones a little under, at, or slightly above FTP, says that you could maintain it for 30-90 minutes, which confuses me because I thought FTP means you’re maximal effort for 20 minutes…? But @Sir_Brian_M you mentioned that SF FTP is done in a fatigued state, so maybe that’s deal. But since FTP is talked about so much in cycling I wonder if in general it means the same? It’s also interesting you mentioning paying attention to your breathing vs. power/HR. Right now when I ride outdoors, I don’t have a power meter yet and I have to look at my watch to see my HR, so I tend to feel out my breathing as more of an indicator.

@emacdoug Thanks for this! I might start incorporating running back in my training and this will be a helpful reference. It’s funny, thinking about my track training days in high school (25-30 years ago), yeah, we just ran about as hard as the coaches told us too, and that was it! I didn’t have anything besides how hard it felt and my breathing, and thinking about other race paces to give me some sort of sense of what I was doing.

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FTP is by definition the power you can maintain for an hour. This is usually approximated from a shorter test interval which is where the 20 minutes comes into play.

Many FTP tests have a short duration max interval to scrub off any anaerobic contribution to your FTP. This is followed by the 20 minute test. FTP is calculated as 95% of your 20 minute average power.

That traditional test protocol often estimates a higher FTP than you can actually hold for an hour. The SF 4DP provides a closer approximation since it preloads more fatigue prior to the 20 min interval. Because of that SF uses 100% of your average 20min power.

But the way we model training load and fitness is changing as better tools and more empirical evidence is able to be analyzed.


@Sir_Brian_M oh man, THANK YOU for the clarification, I’ve been a moron in understanding FTP lol. Got the 20 minute thing in my head. Thanks so much!

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@Sir_Brian_M one follow up question as I think now I’ve been confused about all the 4DP :stuck_out_tongue: What’s the duration indicated by MAP? I had thought 5 minutes, but thinking now that sounds silly, but what’s duration estimate for that? This really has helped me understand pacing better now especially off my trainer.

5 minutes


The only approximate value is the hour FTP estimate

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Thanks @Sir_Brian_M !