4DP Running / Running Power Meter

This week I am completing my pre triathlon prep plan. Two days ago, it was time to challenge myself on a new full frontal ride - which went pretty well. Today, it was time for my 5k running test.

Right now I am sitting in the kitchen with my results and I am calculating my new Running RTHR & RTP. Afterwards I will put all the data into my garmin account (if they are up and running again) and use my running watch to guide me through all the sessions in the coming month.

The whole process just made me wonder…

I read plenty of times how, for bicycling, the 4DP method is so much superior compared to the traditional ftp calculations, and yet, for my running I only have one number to base all my training on. My 20minute effort.

What do all of you think? Is running different from biking? Is this enough?
Maybe it‘s time to bring a more modern approach into the system?

I understand that it‘s hard, or even next to impossible, to gauge the power output during running, and this is probably a big part of the reason why it‘s not done. Does anybody have any experience with a stryd or garmin running pod, which - if I understand correctly - gives me an power estimate.

I am interested to hear your thoughts on this.

Me personally, I would love to tweak my running routine a bit. Partly, because I love the by-the-numbers approach of training and partly because I feel that my training sessions are sometimes a bit lackluster and not fully result-driven.

Most of the time the rough guide of how I feel (RTP) together with my heart rate (RTHR) and percentage of pace of 20min effort (RTP) serves me well. But you know, I am always looking for improvements of the systems I use.


@Pierre you might find the PowerTap PowerCal useful (if you can find one since Quarq bought PowerTap). It uses an algorithm based on your heart rate to provide a power number. It isn’t as accurate as a power meter with a strain gauge but I’ve found the numbers to be very consistent over time so if you have an interval workout that you repeat often - the numbers will start to have meaning. On the bike it does average power for the ride pretty well, short NM sprints are definitely it’s Achilles heal. But if you use it for what it does well, I think it can be useful over time to understand your form against fatigue.

Thank you, @DancingCyclist, for the suggestion.
But the whole point in using power is to have a more reliable metric than heart rate - for me at least.

I kinda like the idea of stryd but don’t know if it will provide any benefit to my training. Like I said in my initial post, I would need to get the minions on board since they are responsible for my training plans.

How does the verse go:

In Sufferfest we trust.

I’m also pretty curious about the stryd

@Pierre I agree with that verse!

I’ve had a Stryd (well, 3 actually!) in the past. Definitely a solid tool to bring power to running. Also, the Stryd folks have done great work to bring their tech into the fold of modern power-based training methods previously popularized by cycling and rowing. Their race predictor tool is cool and pretty accurate!

That being said, I stopped using my last one (dog ate one and I sold another) because I actually got turned off from how “serious” / “methodical” / “rigid” it made my running. To explain, I’m prone to being driven by my numbers, and if you think you’re susceptible to being pace-driven, running power will drive you even more. If you can avoid the obsession, it can be a great tool, especially for trail running and similar situations that make pace a difficult metric to use.

So to sum up the ultimate questions on this issue .

Is HR less reliable than power? Pace? Time trial on a fixed course?

IMHO … in order:

  1. Time trial on a fixed course
  2. Power
  3. HR

Will running power improve your performance / is it necessary to improve your performance?

IMHO …Nope.

Is it fun to nerd-out on the data and distract yourself with yet another source of training data?

IMHO … Yup.

Bottom line, if you’ve got the money and the discipline to use the tool in a focused way, go for it, but you probably don’t need to.


This made me spit out my sip of water… :slight_smile:

We are two of the same mind.

You are absolutely right that I don’t need it at all to improve. Hell, I could even argue I need none of the tech or gear I collected. Just heading out and doing it is enough. But like you said, sometimes it’s fun to ggek out a bit. And I think a small part of why we are all here, on the Sufferfest, is because we like numbers, or at least the training it allows us to do.

So maybe to pivot the discussion away from the gear and more towards the training: 4DP Running.
Why should I be satisfied basing all my workouts just on a 20min effort number instead of treating it the same as my biking?

Minions, please give me the Full Frontal Running Test! :japanese_goblin:

Well, Stryd will give you your running power curve if what you’re looking to improve is a certain range of it relative to the rest.

I guess my warning here is that it your running power curve won’t necessarily inform you on how to train as much as you think, especially if you’re splitting your time with cycling.

There’s only so much volume of running per week to modify, unless you’re training in very big volumes (like … elite and pro volumes).

PS: The dog and I have gotten over him eating the Stryd and the expensive shoe it was on. :wink:

I have a different device that gives power (Runscribe pro) for both feet. I think it’s quite funny to see how different the number can be from the same device during the same run. Basically my right leg is awesome and my left sucks. It would be the equivalent on a bicycle if an asymmetry of 30% or so.

I did think for a while it might be something worth changing but I’ve realised it’s nonsense. Running Power is never going to be anywhere near as useful as cycling power. The one variable they could be most useful for, unpredictable head winds, is the one they are worst at

I used to run under a very good coach, I was the 2nd slowest in a group of around 20 runners, but was still knocking under 35mins for 10km. Did we ever train to lactate threshold? Most definitely. Were all of our varying paces based upon lactate threshold…definitely not!!

Our training paces were based upon our actual or our target race times. Here is an example of a session I remember well:

3 miles at lactate threshold
3mins rest
2x1 mile at 10km pace off 1min rest
3mins rest
2x1km at 5km pace off 1 min rest
3mins rest
2x600m at 3km pace off 1min rest
3mins rest
4x200m at 1500m pace off 30secs rest

So, using that as an example, NONE of it, aside the LT pace effort, was based upon LT pace. This is because, for example “runner 1” may have had an LT pace of, say, 5:15/mile and a 1500m of 4:30/mile, yet runner 2 may have an LT pace of 5:40/mile yet a 1500m pace of 4:15/mile.

I think the best thing for running is to get various race times and work out your splits for a given time. You could, in theory, do your own 4DP test and go from there of course.

RE Stryd…I think the issue here is that if you’re running in muddy conditions, or particularly windy conditions its likely to be less accurate. It is never going to be as accurate or consistent as a cycling power meter. Personally, I do not see it as a necessary tool compared to a cycling power meter.

For reference when I was training with that group, I had a faster LT than a few runners, yet my 1500m time was the slowest in the group (4:18). I have a poor anaerobic system in relation to my aerobic system.


I ran with a Stryd meter for a season in 2017 because I love collecting data. I found that it wasn’t accurate enough when used with different shoes or on varying surfaces. Overall I found a combination of pace and RPE to be a much better measure and also more practical.

You should check out Steve Magness and the Science of Running for a view of how to use a multi pace approach for running. Although I have no idea how it would be applied to triathlon training.

I used Jack Daniels’ system for a few years and really struggled with the single VDOT as my ability at 800m/1500m was significantly better than 5K/10K which was also way better than my half marathon pace. Towards the end I started using four different values which seemed to defeat the purpose of it.

I find it funny how nobody in their right mind would base marathon training speeds off 400m ability yet somehow it is a good idea to do it the other way around.


Hello! Heart Rate is the limiting factor however RTP & RPE should never be left by the wayside. The Stryd has improved over several iterations. When comparing running power training zones to cycling power, the running power training zones are far more incremental. When setting up the device I recommend following the Stryd protocol and performing a 3 and 9 minute Run Test as well as a 5 km Test on a repeatable course, as well as utilizing the same equipment. Test workout sessions such as 4 x 5 minutes @ Zone 4 are very helpful and I would recommend executing once per month to gauge progression.

Running Economy and Leg Spring Stiffness are two aspects that I utilize with my athletes and I think you would find very beneficial. Click on the below link when you have sometime to read more about it-


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