Sports Watch Performance Comparisons: Vienna City Marathon

At the Vienna City Marathon, I ran with Suunto 9 Baro, Polar Vantage V, and Coros Apex.

Let’s compare!

The watches used different GPS systems, which isn’t ideal for comparison, but happened. oHR came from Polar and Coros; the Suunto recorded HR from a Polar H10 heart rate belt.

GPS Tracks

My focus was on the GPS; and that is easiest to compare. And hard to interpret, because the results show some distinct issues – from all the watches, at various times.

The difference, at least in distance, which was ultimately recorded was not so divergent between the watches, nor is the track so consistently off from reality, that one could determine a single device that performed much better than the others.

There is only one exception: I also had my smartphone, a Samsung Galaxy S9, record the track with the Strava app… and that GPS track is oftentimes quite noticeably far from where it should have been.

If you want the full presentation from me, here’s the YouTube video:

If you are coming from the video and want to have a closer look for yourself, you can use this map:

Full distances recorded were:

  • 42.34 km from the Samsung smartphone (Strava app)
  • 42.92 km from the Polar Vantage V
  • 43.19 km from the Coros Apex and
  • 43.36 km from the Suunto 9 Baro.

Looking at the watches, the biggest gap is between the Suunto 9 Baro’s and the Polar Vantage V’s distance – and that is 440 m difference over 42-and-some kilometers. That is 1% difference…

As usual, if one wanted to find examples of any watch having performed badly, they would be easy to find.

There is one place where I am quite certain that the watches I had on my left arm (the Suunto 9 held over my hand, the Coros Apex on my wrist) were affected by a reflected signal (from a building on the left).

GPS signal reflection issue, most likely
GPS signal reflection issue, most likely

The canyon of houses that the Mariahilfer Strasse goes through was also less than ideal for GPS reception, apparently – but that affected all the devices.

Mariahilfer Strasse Offset
Mariahilfer Strasse Offset

Then again, why the run along the Donaukanal canal should have resulted in highly “wobbly” tracks, I don’t know. And there, it affected all watches again, but at different times. So, this is really rather mysterious.

Strangely wobbly tracks along the Donaukanal
Strangely wobbly tracks along the Donaukanal

I’ll say, this is all within the normal bounds of GPS technology and its limitations, though.

Pace, Speed, Cadence

Pace data displayed during the marathon seemed rather dubious; I remember having looked at it at a point where there was a 1 min/km difference between the paces shown on two of the watches.

Comparing the recorded data for pace/speed is a bit difficult because the data export from Polar Flow does not include that data.

Thus, we can directly compare the pace/speed from the Suunto and the Coros, but not the one from the Polar. Polar Flow displays the pace with the values on the y-axis exactly opposite to how the comparison tool I use,, does it…

Pace data from Coros Apex and Suunto 9
Pace data from Coros Apex and Suunto 9
Pace data from the Polar Vantage V, adjusted to fit the above graph
Pace data from the Polar Vantage V, screenshot in Polar Flow and mirrored to have the y-axis as in the above graph

Still, apart from the extreme value(s) at 24 minutes in (where I had to stop at a tree…), the paces are somewhat different, but within a comparable range.

Cadence is also quite okay between the different watches.

Cadence graph from Suunto 9, Polar Vantage V, and Coros Apex
Cadence graph from Suunto 9, Polar Vantage V, and Coros Apex

Heart Rate

Heart rate still requires a dedicated discussion, but I still don’t quite know how to go about it. Winter weather is not good for oHR, many factors influence it, and I feel that I have had some decent results and some very bad ones.

The oHR performance of the Polar Vantage V and the Coros Apex here at the Vienna City Marathon was rather appalling.

HR data from Suunto 9 (recording from Polar H10 chest strap), Polar Vantage V and Coros Apex
HR data from Suunto 9 (recording from Polar H10 chest strap), Polar Vantage V and Coros Apex

There are sections in the middle of the run where the values are not too divergent (and not too different from the heart rate recorded with the Polar H10 heart rate belt), but there are also some divergent values.

At the beginning and, perhaps especially, at the end of the marathon, the values recorded by oHR are very different from the values most likely to have been real, the ones recorded by the heart rate chest belt.

The H10 did slip down my chest quite a bit towards km 32 or thereabouts, though, so maybe even that recording received some erroneous signals…

Wonder what it looks like to run the Vienna City Marathon? I have a video that shows it on my YouTube channel:

We will shortly have a look at GPS performance in the Alps, during a rather unusual tour (which was a while back already), data from two recent runs in Florence, Italy… and one more marathon is coming up real soon.

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