Running Power – Comparison – A Windy, Hilly Run with Coros, Garmin, STRYD, Polar

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Running Power Comparison

Today was windy. Today was a ‘rest day’ (hah). Today was a day for running up some hills on paths and on dirt to check out how the Big 4 running power competitors compared to each other in real-world conditions. I performed a similar test a few years ago (link) but since then STRYD has introduced a new pod, RunScribe has taken a back seat in the consumer market and Polar+Coros both introduced their own versions of running power calculated solely from within the watch with no need for any additional accessories.

Today’s purpose was to test out something with the Apple Watch 6 but I couldn’t resist donning 4 other watches to break my ‘watches worn’ record (5). Here’s the kit I used for today’s test in the popular running spot that is Richmond Park, London.

Conditions: 20mph NW Wind,  14 Celcius, 4-6 ‘hills’ of between 50 and 200m depending on your definition of a hill. All hills were under tree cover at times, one was next to a wall (think wind), and all except one were off-road but on fairly firm ground. The hills are all fairly steep approaching the summit, I’d guess well over 10% but I don’t know exactly.

Overview Chart

I used dcrainmaker’s dcranalyzer tool with smoothing initially set to 20 seconds and I’ve circled the ‘hills’. from a technical perspective, the Analyzer tool is the easiest way to compare developer fields. There are other ways but they are a PITA.

It looks like Polar and Garmin show similar results. I guess there is some similarity but, as this chart shows, there are differences between them too

Coros and STRYD are similar, which is surprising as Coros can’t take into account the wind. Luckily Ray’s excellent software lets me add in STRYD’s WIND POWER as separate line (it’s still included in the total as well). The chart clearly shows that STRYD and Coros can agree when there IS a STRYD wind effect but that they can also be very different when there is little or no wind effect.

So that was interesting but that’s about it. I don’t think it’s worth my while spending any more time comparing the different forms of running power until there is a way to determine which is correct. I think that was the same conclusion I drew 3 years ago too.

One take out could be that these are 4 random number generators but I will still stick with my random number generator of choice…STRYD…from experience I found that it is a good proxy for effort and my guess would be that it is correct. Of course, I could be wrong.

I’m not sure you can conclude anything from this data.


Notes & Further reading

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As there’s no standard for running power then maybe normalise all data to its average value. At least then you’ll see whether the devices are consistent or if they record +5% on one hill but then +8% on another.


I’ve tried a Garmin Instinct, Suunto 9, Garmin 35, Polar M400. A lot of wasted money on things that had different results and will be “outdated” in 3 fact the M400 was the most accurate of the bunch.

Regardless, I run with a standard time piece with a stopwatch and go by how I feel at the time. To me its more fun than worrying about metrics. Running is being made into this complicated and expensive thing when running is exactly opposite of that.

Gary Coyle

Hi I’m curious, when I run let’s say hill work my garmin 945 will have a negative performance ormand if its windy. This also happened when I run with a running vest on with 1 litre of water. Is there anyway I can set the watch with to reconize Hill wind ect I also have the standard chest strap.
Look fwd to your comments.
Kind regards
Gary Coyle


It would be interesting if you could add to your comparison the power calculated by Strava and Runalyze – this happens regardless of running watch used.


Neat idea, but you should label your axes. What are you measuring on the y-axis? Ought to be watts, and it looks like you are measuring dropped data. Not so interesting. If you mentioned in text, I missed it.

tfk, the5krunner

hey it’s watts. the legend says it’s power, which is measured in watts


Might be too late on this and get no response now but here goes anyway! Having unfortunately damaged my Vantage M I’m on the hunt for a replacement. First port off call is the new Vantage V2. Primarily because I fancy having a play with running power, but also because I think the Polar watches look the nicest (important obviously!) and I’m also a long time Polar user so well invested in Flow with data and don’t use Strava etc so Flow is my only place with this data. Maybe not the best way of doing things. My question then really is how useful is ‘running power’ when natively calculated in the watch? I believe the data the watch’s or pods give is largely just a number that has no agreed methodology and agreed standard so Styrd will give a different valve to Polar to Coros etc but in reality does that matter? Can you still take Polars numbers and make use of them in a reliable way or is the general belief that the in Watch numbers are a ‘nice to have’ but if serious get a pod such as Stryd? I’m not totally against a change from Polar,… Read more »

tfk, the5krunner

it’s never too late to get a response 😉
1. aesthetics…agree!
2. flow – yes stick with where your data already is
3. NATIVE running power….aint gonna be accurate. its free so just use it to get a feel. there will be a degree of actionability. upgrade to stryd when you are ready 😉
4. there are two basic methodologies. stryd and coros are in one camp and their number will NEVER agree to polar. and YES that is a problem as your power numbers wont transfer across from polar to stryd. however a couple of weeks running will soon give you a new CP/FTP after you switch
5. a garmin 245 would work with stryd. apple watch se/aw3 will work with stryd. the coros pace 2 bundle with stryd and my discount at new running gear is super cheap but be mindful that only coros have stock right now


Cheers. Appreciate the response.

So basically. Native is fine to start, but, a pods better in the end.

Tempted by that Coros deal, once its in stock again that is(!) basically a watch for £100 that I could probably get back if I don’t get along with it. Not sure I could wear the watch 24/7 although i’ll be honest I haven’t researched that watch fully. Something to check out.

The quandary is, do I really need to spend so much for a load of bells and whistles I might not use. real risk of being ‘over watched’ for my needs. Really do want to try power though and it looks like the Coros deal or indeed the Coros alone is the easiest way. Some more thinking to do. The Vantage M still functions for now but the screen is damaged.

tfk, the5krunner

yep, those are all personal thoughts