Coros Effort Pace Gen 2 – the improvements start

Coros Apex 2 Pro track run

Coros Effort Pace – the improvements start

It seemed that Coros encountered a few issues with the capabilities of its Running Pod 2. Those issues might have been linked to avoiding a breach of Stryd‘s patents in the area. Perhaps as a result of that, we saw the launch of the Coros Apex 2 Pro take a different tack with a proprietary concept called Effort Pace.

Effort Pace & GAP/NGP

Grade Adjusted Pace (normalized grade pace) is an old concept where your pace is adjusted to the equivalent pace on flat ground. The adjustment only considers the effect of slope/grade.

Despite being a longstanding concept even Garmin has only recently managed to introduce GAP. So it’s not unreasonable for Coros to innovate here as well.

Phase 1 for Coros Effort Pace was simply making Effort Pace and GAP the same.

Coros has just released Phase 2!

the Change to Effort Pace

In a Nutshell: Effort Pace now includes a factor that relates to how well you handle running a particular gradient.

Coros try to explain the change to Effort Pace a bit more at this link but I didn’t quite understand all the nuances so I reached out to Coros and got some clarification, although I’ll admit to still not being fully clear by the end of the process.

It works something like this…

Learning Phase: Over a period of several weeks, the Effort Pace algorithm learns how well you run over all uphill and downhill slopes in increments of 1 degree. So for each degree of slope Coros assess what happens in the relationship between your heart rate and speed. My assumption here is that you get a personalised scaling factor for your pace on every degree of slope.

Running: Your new personalised effort model becomes live at some point and effectively adjusts the old GAP calculation by applying an additional factor for every change in grade.

Adaptive Phase: The scaling factors are not re-evaluated during a run. However, the relationship continually reevaluates as you run more and give the algorithm more data.


I thought there might be problems with heart rate lag and various biomechanical or personal performance characteristics at different speeds or based on fatigue changes from one day to the next. But this approach at least has the potential to address some of those.

Q: Is Effort Pace another way of measuring Running Power?

A: I’m not sure. It’s certainly Coros’s commercial alternative to running power.

I guess the reality is that Effort Pace is going to be something broadly similar to running power but with different pros and cons. The biggest positive to be said for it is that it uses a metric (pace/speed) that’s expressed in a way that a large number of runners intuitively understand…unlike power.

Is Effort Pace Better Than Running Power?

I’d say, as of today, the answer is, “that’s highly unlikely“. There just isn’t the science or even a detailed explanation from Coros about how it works and how they tested it.

But one thing to mull over is this. If you run for one minute at 500w on the flat and then, the next week, run one minute at 500w up a 10-degree slope. Will your execution be the same and will the impact on your body be the same?


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9 thoughts on “Coros Effort Pace Gen 2 – the improvements start

  1. My unscientific view. Effort pace is going to be a mess. But like you said, at least it’s talking the language runners use. So far more likely to be experiment with by the Coros community.

    Slight more sympathetic view. If it has the effect of making runners slow down more on up hills to better pace their efforts, then that’s success of sorts.

  2. Just a few months ago Coros came in with a perfect integration of the Stryd foot pod. Now they doing their own thing and I wonder if they stop going on with the improvements of Stryd. Do you know if they will bring in the new metric of the shortly launched Stryd Gen? Or must I do a double sync like it is with Polar and Suunto?
    I was waiting for the Apex 2 such a long time. Now it is available but I‘m wondering if it will be the perfect watch for using the latest Stryd…?

  3. I understood Coros adjusted pace was their own original calculation pegged to velocity at vo2max factoring in grade in a similar way to stryd does with there power number, rather than the standard version of GAP, this was pre there effort pace…

  4. > But one thing to mull over is this. If you run for one minute at 500w on the flat and then, the next week, run one minute at 500w up a 10-degree slope. Will your execution be the same and will the impact on your body be the same?

    No. Holding aside whether power is actually captured accurately by any sensor, the biomechanics and muscle recruitment is different for flat vs gradient.

      1. The advice to hold constant power on an undulating course is too idealistic for sure.

        The message needs to be simple in marketing world.

      2. I’m more of a running power skeptic than I used to be. I think these are all tools that have value (or maybe some don’t) but none is as useful as power for cycling. “Natural” movement is much more complex than cycling which is very efficient at isolating muscle groups and training you to systematically recruit them in the most efficient way. The simple model of watt power for cycling is a much better fit for cycling than running — or in decreasing validity: trail running, scrambling, climbing, parkour — while it is simultaneously fairly easy to capture accurately in cycling and fiendishly difficult to *infer* for running.

        Subjectively I ran up a ~2km 4% avg grade yesterday at approaching 500 watts. I then turned around and ran down and was unable to get over the mid 400s in watts. But the point is that I can say my muscle recruitment was totally different and those watts were not remotely equivalent. The down at lower wattage took more out of my quads than the up took out of any part of me.

        I think running power has a use but it’s just not generalizable the way cycling watts are. And I don’t expect that to change anytime soon or maybe ever.

    1. Well, maybe ‘yes’ is also an answer because what does impact mean here. If it’s meant how much calories you need, maybe it is the same, if you are trained for both, flat and stepper runs. There is so much unclear wording…

      I am used to use power for years and Garmin’s GAP did not represent values that match my effort (compared to power and heart rate). For me, I take 3 values into account when I am trailrunning: power (which is actually great even for very steep trails >10° with the new Stryd), heartrate and VAM

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