Hi, I’m new and just started testing out Intervals yesterday and am quite impressed with it so far, especially considering it’s free compared to TrainingPeaks for example. However, I did encounter an issue when importing my activities.
I first connected to Strava (after which, if I remember correctly, things at least seemed fine) and then also imported the data from Polar. Now I see some of my activities with huge spikes in load. This is how my Fitness graph looks like
My Afternoon Run on Monday Aug 1st (for example) has a load of 4198. When I look at the activity, I can see that this seems to be connected to the pace load as I see Heart Rate Load as 171 and Pace Load as 4198 (and my Training Load Priority is Pace, HR, Power). I already corrected a couple of these fringe extreme cases but am now wondering what is the cause of this, and - more specifically - are the loads off only for these very obvious cases or are they off for all of my activities? Furthermore, is there a quick way to filter out the cases where it’s way off (for example, see all activities with a load of 1000+)?
I saw in another bug report the solution for something similar was to switch to HRSS but I already have that on.
If this is simply an issue on priority, I don’t mind changing it to HR, Pace, Power (I don’t want to use Power as I don’t understand it at all and the more I try to understand it, the more I see there’s no real agreement on running power anyway) OR keeping it as it is and just correcting the edge cases manually but I’m still concerned about the reliability of the results overall.
There are different possible reasons for this to happen:
Since you have the Pace as highest priority, I would start checking if the Threshold Pace and Pace Zones are setup correctly.
If those are correctly set, check your activity charts for hiccups in Pace values which might be due to erratic GPS signals. Check the charts visually and also check the Max Speed by making a selection of your complete workout and adding Max Speed as a field.
If no pace is present in your workout file (for whatever reason), intervals will use HR. Same goes here, check your HR settings and again the chart and value for HRmax.
Once you found the source of the error, you can correct and reanalyse the activities that have errors or even all activities with the new settings by using the Update Activities button in the settings for the different disciplines.
If you are unable to find the source of the errors, post some screenshots and I’m sure we will figure it out.
Hi, thanks for the very quick reply, very much appreciate it! Based on your advice, I did find the error indeed: the pace seems to be completely off for the activities with issues. I wasn’t able to find and “average pace” in the options but the average speed shows +50km/h (30+mph) and the max speed is more than four times as much. The Pace field itself is correct.
Now, the question again is: what might be the cause of this and how best correct this? I checked the same activity from Polar Flow, Strava, TrainingPeaks and sporttracks.mobi and while there was some small discrepancies among them, they did seem roughly correct whereas intervals.icu seems pretty much completely off. Should I just prioritize HR and forget about the pace, or do I have some other options.
Most of the time it is caused by GPS anomalies or incorrect Elevation data.
Do you have Grade Adjusted Pace selected?
If your device has inaccurate elevation information, the GAP calculation is wrong. Try setting elevation correction and GAP model to None to see if that has influence. You’ll find those in the settings for running under Pace zones.
Thanks for your continuous help. I changed these and now Fitness graph seems more or less like it does on other apps, and the Loads of the completely messed up Activities seem more or less normal as well.
The strange thing is that when I look at the activities, the max and average speeds do still seem completely off. So it looks like the Load was probably fixed but I don’t understand why, when it still seems to think I’ve been running almost as fast as a car.
Did you “reanalyze” after the settings change?
Please post a screenshot of the map for an activity with irregular pace. I would like to see the accuracy of the GPS track. If GPS anomalies regularly put you off the road, you can have very strange effects. Especially if you live in a hilly region.
Here’s a screenshot of one of the runs. It seems quite accurate and the area isn’t very hilly either.
I don’t know if this has any significance (probably not) but I also think I calibrated the watch just before this run, so the elevation data probably should have been correct. That said, I have no idea how accurate the calibration is and I haven’t verified it with anything, just used the calibration feature of the watch.
I have a copy of the fit file and checked it in Golden Cheetah. There is a big problem with the speed data but also other data is erratic. First 28 min are more or less Ok but then the GPS reception got lost, came back, stalled…
Resulting in a useless speed track:
Power data is available untill 28:30min, and then nothing anymore. There are big gaps in latitude/longitude data (GPS data) but surprisingly, the distance keeps increasing at about 2-3m/sec which can be considered “normal” running speed. Then sometimes lat/long is available and distance increase is normal but the speed data is zero.
I don’t understand what exactly went wrong but there is a problem with your devices/sensors.
What exactly were you using?
Here is a snippet from the FIT data:
Another messed up run is Intervals.icu and I now noticed that they both seem to only be synced only from Polar (I presume that’s what this means?)
Could this have something to do with the problem? Both of these runs ARE synced from Polar to Strava too, and seem fine on Strava. Here’s the pace graph from Strava for the run MedTechCD was checking
Looks like Strava reconstructed your run in a pretty clever way by using stride length for the parts where lat/long data was missing. Most watches do this for short parts where GPS data is missing, in the woods for example. But then again, when this GPS errors keep occuring, stride length will be wrong in the end because average stride length is calculated from GPS distance and cadence.
Syncing them from Strava is only a workaround but certainly not the best solution. You should check why satelite data gets lost this often.
Can you see an obvious reason why your GPS data is this errratic? Are you wearing something over your watch for example that could cause satelite loss? Or is the whole run done under thick coverage by trees?
And for what reason is the Power data missing after 28min? Does the Vantage have wrist power or are you using a footpod?
Found some talking on the net that Glonass (Russian satelite system) is regularly being disrupted under the actual circumstances and Vantage is by default set to GPS+ Glonass.
Might be an idea to try and change that to GPS+Galileo? Should be more accurate anyway with the European satelites.
This is all very interesting. Is there a way for me to check whether or not the GPS data is getting lost without diving into the FIT file (which I’m sure I won’t understand)? I mean, these runs seem normal on Polar Flow and Strava so I wouldn’t have been even able to find out this problem had it not been for this pace issue on intervals.icu.
As for your questions, on these runs I wasn’t wearing anything over the watch. There is some tree coverage (not really a proper forest but kind of a forest area) for about one third of the run, but the rest is pretty much wide open.
These extreme cases were only a few runs on intervals.icu as well, but do you think it’s likely that the GPS data is messed up in the remaining of the runs as well, and it just doesn’t show because of they’ve been synced with Strava as well? I run more or less the same route ever time, so I’ve run this dozens and dozens of times this year alone.
Happy to try changing to Galileo, just wondering whether I’ll ever be able to tell if it makes a difference
You will see the difference if you continue using Intervals. Your data, speed chart, max and avg pace should be “normal”
But I wonder if you recently saw strange problems/issues when starting your run? Does it take longer then usual to lock a minimum number of satellites before you can start your workout for example?
To get the most accurate data for a run, you need good GPS data. Stride length is ok to fill in some gaps where the GPS data is less good but clearly, stride length isn’t a constant. It is significantly reduced when going uphill…
When synced from Strava and Polar, do you still have the ability to download the “original” fit file in Intervals? If so, someone might know a tool to quickly check the RAW GPS data (the pure lat/long numbers) and not the track already corrected by Strava and/or Polar.
What I did was loading the FIT in Golden Cheetah and then I checked the RAW data. It was immediately obvious that a lot of datapoints were missing the GPS data. The modern tools try to compensate for that and do a really good job. But my believe is that they should notify the user if too many errors need correction, so that you can take action to improve.
Ah, but this is what I was trying to point out Out of perhaps 60 runs even Intervals showed issues only with maybe 5 of them. For the rest the speed chart, max and average pace etc were seemingly correct. Perhaps this is because of the Strava sync (could maybe try to un-sync strava and see how things seem if I only sync with Polar, or analyze the original FIT file) and there’s been issues with all of the runs but if not, it seems to affect only about 10% of the runs so far, and thus spotting whether or not switching satellites helped or not might be a challenge.
I have been meaning to try Golden Cheetah anyway, though, so maybe this is a chance to (try to) have a look. It looks awfully complicated
I haven’t had issues with starting my runs, no. It tends to take maybe 5-10 seconds until the GPS “locks in”. I have to say that I have noticed the speed being a bit “jumpy” in those more foresty areas of the run, but I’m not sure if this area is really the problem. I checked the map and while you said the first 28min or so seem ok, the “worst” area seems to be behind me at that point already. There are some trees surrounding the route after that as well, but not as much, and after 45min it’s pretty much open sky. This feels like a very weird problem.
I wonder if the problem could somehow stem from the conversion of the file? If I have understood correctly, there is no way to export from Polar straight into FIT. I now exported one of the troublesome runs (the one you analyzed on Golden Cheetah) into GPX, opened it in Google Maps, and the route seems fine.
Admittedly I don’t know if this could once again be due to the device compensating the missing GPS data…
I’ve checked the map in GPS Visualizer: Draw a map from a GPS data file and it looks quite good but when you check the lat/long datapoints, there are big gaps. I’ll export that this evening from golden Cheetah to a csv file and will send it to you. Can’t do it now because I don’t have Golden Cheetah on my business PC.
Golden Cheetah has a steep learning curve but it has always been one of the most advanced workout analysis tools. For this basic check, you just Import from file and go to the Edit tab where you have all the columns with data. I have to say that I am only using it occasionally the last 6 months or so, because intervals is getting just as good and is available online
What I’m still wondering, is why there is about 28 min of Power data, and then nothing anymore. The end of the Power data stream is where the errors start to occur. Can you find an explanation for that?
Nope, no explanation for that. On Polar Flow I can see a power curve right until the end, and it seems to roughly match the HR curve as well as the pace curve. But like I said in my first message, I don’t really understand power at all so all I can tell is that it rises and falls roughly at the same time with the other two curves.
I installed Golden Cheetah and have checked a few files now. Presuming that I have been checking the right data (Latitude/Longitude on the Edit tab), I don’t think the GPS data is the sole cause of the problem on Intervals.
On Aug 1st I ran an 18km run, where Intervals reports my Avg speed as 53.2 and max speed as 216.5km/h. According to Golden Cheetah, the Lat/Long information is missing only for about 10 seconds during this run. As a comparison, the 10km run on Aug 3rd has a 40 second gap in the GPS data, but Intervals reports its Average speed as 8.2 and max speed as 22.6km/h. The max speed is obviously too fast for the second example, but there it sounds somewhat accurate considering the longer gap in GPS data whereas in the Aug 1st run the 216km max speed doesn’t make any sense at all.
The common problem with the files that I’ve checked was the missing power data. The files where the speed was completely messed up were both missing the power data for most of the run. I don’t see how this would explain the problem either though, but like I said, I don’t really understand power.
After all this digging I’m now wondering what to do. I’ve now changed the satellite to Galileo and have Golden Cheetah installed so I can keep an eye on whether or not the GPS data seems better. That said, I’m wondering if an easier solution would just be to prioritize HR over Pace. With that I’d know the Loads are more or less reliable.
On the other hand the Fitness graph and the speed-based load do LOOK pretty normal after I turned off the Elevation Correction and the GAP model. But because the speeds of some of the Activities are still messed up, I can’t really even guess how correct the speed-based Load is, and am back to wondering whether prioritizing HR would after all be the better option here.
There is obviously something wrong and the best solution would be to find out exactly what is wrong. The HR load would be just a workaround and leave you with absurd pace/speed data. At the end of the day, pace is an important metric to track performance improvements.
The speed field is normally populated by data from a dedicated speed device, like a an rpm counter on a bike wheel, or in case there’s no such sensor, by a distance calculation based on the GPS data taken every second. I haven’t checked the exact uncorrected plots of the GPS data but the lines with erratic speed fields should have bad GPS data. Bad GPS data is just as problematic as no GPS data.
I’m not giving up yet, there has to be something we are overlooking.
If you check the activity on a Polar app, is the Power data available for the whole run? I have a feeling that both these problems are somehow connected.
There is not that much to understand regarding Power. The advantage of power is that you have a target metric that is independent of incline, wind, terrain… Pace is strongly influenced by those and thus difficult to use as a guidance for intensity during a workout on rough and rolling terrain. HR is influenced by heat, fatigue, lack of sleep… Just look at Power as an intensity metric that is valid and equal in almost all circumstances and thus more easily comparable from one run to another.
