Interval Training Data from Polar Grit X vs. Vantage V

After an easy first run, just to get started, and a first look at Hill Splitter‘s working, now for some high-intensity intervals.

Again, the comparison is between Polar Vantage V and Polar Grit X, with heart rate data from the Polar H10 as comparison.

Here, the Stryd worked as it should, so I’m also adding its data where worthwhile.

Heart Rate

First data: HR values from the oHR of the Polar Grit X and Vantage V vs. the H10 chest HR strap.

It paints the usual picture: We do see improvements on the Grit X, as compared to the Vantage.

After a first vacillation, the values from both Polar oHR sensors are pretty good during normal running, but the Vantage shows more issues, more often (see at the very beginning and during the cool-down running).

During intervals, the Grit X also looks to have worked better than the Vantage V, but it does have its issues.

This is not particularly surprising; sudden changes in intensity are a big problem for oHR sensors. It’s all the more interesting to see how they worked.

Interesting also to try and use the respective graphs from Polar Flow for comparison or interpretation:

Some of the differences are easy enough to spot, but the values don’t look all that different.

It could be that I didn’t run the intervals as consistently at maximum intensity as I should ideally have. A look at the curves in, now zoomed in to just show the intervals, disabuses of that notion:

The heart rate captured via the Polar H10 shows very clearly what was an interval, what a recovery phase. It’s the values/curves from oHR that make the issues.


Usual issues with looking at the data for speed/pace, the way I recorded them…

In fact, two usual issues, here:

1, The recording from Racefox Run does not get smoothed; it’s just raw data. Which is why it’s so spiky, it wouldn’t help anything even if it didn’t range so far that this alone makes things hard to see.

2, Polar’s data export does not actually seem to include proper pace data (certainly not from the Vantage V), even as it includes data that looks like that (to, the tool I use for comparisons, at least)

Gotta do this differently.

The upper of the following images, therefore, shows the pace graph from the Stryd sensor; below that are the graphs from Polar Flow:

I’ll say, pace was recorded very nicely. Stryd is more sensitive and quicker to “see” a stop where the Polar watches have not (yet) shown that.

All in all, though, the values (or at least the curves resulting from) are rather comparable and make it very clear what was an interval, what the recovery.


Cadence, just for a quick look at that:

This actually also works well with Quantified-Self and with the data Racefox Run records off the H10:

Not sure what makes Racefox Run not see any change in cadence (but neither, zero cadence) when I’m moving slowly or stopped, but that’s a different issue.


Running power… Flow doesn’t make that all that easy to see, painting it in a red line on a yellow-to-orange background:

We can also have a look at these values in Quantified-Self, compared with the Stryd:

And the values of “power from the wrist” measured by Vantage V and Grit X look pretty similar, and in tendency, so do the power numbers from the Stryd.

It’s very interesting to note that these graphs show not only the usual higher values for power given by Polar, as compared to Stryd. Rather, they show these together with very similar power values from all devices during the recovery phases.


All in all, I’d say that this result is typical for this kind of training:

The Grit X with its Precision Prime 2.0 oHR sensor may give better values than the Vantage V. For an HR-based interval training, a chest strap is still recommended.

Looking at speed-related values as well as power, there are no worries – at least, looking at the data post-training, no matter if from Vantage V or from Grit X.

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