Thanks for explaining.
I enabled "auto-estimate HR and resynced the 2 activities from Strava but I have the feeling that it does not make enough difference in terms of XSS scores (the 2 rides compare now 102 to 127 XSS).
If I look at the numbers in Strava (see below) and imagine to what power they would correlate, I would still have expected a much higher XSS for today’s ride.
So I still have the feeling that there is something fishy with the power/heart rate matching algoritme or maybe my historical power/heart rate data is screwed somewhere.
The Strava numbers
Ride 1 (yesterday)
Avg heart rate: 131 (67% in zone 2)
Max heart rate: 157
Suffer score: 128
Ride 2 (today)
Avg heart rate: 150 (44% in zone 4)
Max heart rate: 175
Suffer score: 255
Thanks again for looking into it and looking forward to your reply.
If you increase/decrease the resting and max heart rate values, you can indirectly adjust the algorithm to reduce/increase the XSS. For example, decreasing max hr, should increase XSS. Experiment with different values if detected ones aren’t correct. You don’t need to re-analyze / re-import activities after making a change. All HRDM activities will be updated.
Thanks for the tip Armando.
Altough I will try to use it, it still is a workaround.
To my opinion the HR/Power algoritm still isn’t working properly and should be reviewed.
But I guess that is not on the top list of the development team
I believe what @xertedbrain means is that power is equal to zero whenever cadence is zero. You can see how many times that actually happens, or at least that’s what that graph looks like to me. And Xert calculates everything including zeros (except XEP, I guess), so that will influence XSS etc. Not an ideal situation, I agree, but they’re working on improving it(?)
It works quite well overall. The cadence is pretty normal for a group ride. Will need to investigate more what’s different about the historical analysis if all the data is normal on the newer rides. HR is notoriously poor and error prone but we do have ways to account for or remove errors. Everything should work perfectly, with great results with reasonably good and consistent data.
I also have the same impression as @johanbarelds. XSS from heartrate derived workouts is way off. I have a powermeter on my roadbike and no powermeter on my mountainbike. If I do a comparable intensity training (feelingwise and from the data in Garmin Connect and Strava), xert rates the heartrate derived workout with the mountainbike as an easy endurance activity with 122 XSS and the powermeter based workout with the roadbike is a difficult rouleur ride with 192 XSS. Can this assessment be fixed?
All bikes are equipped with a cadence sensor, @xertedbrain. But if there is a correlation in the algorithm between cadence and HRM this might be the problem (at least im my case). Typically my cadence on the mountainbike on uphills is 5-10 rpm lower than on the roadbike. Additionally on technical descends there is of course no pedalstroke on the mountainbike as you are standing on pedals, while you can still pedal downhill on a roadbike.
Yesterday I did a short flat gravel ride with the mountainbike just before an upcoming thunderstorm. I was kind of pushing to get some work done before the bad weather and had some short all out intervals on a strava segment.
Xert rated this ride moderate and gave it an equiv power of 149W:
I am aware that the metrics are different and not to be directly compared, but Strava gave the ride an average power of 216W, which is much closer to the feeling I had and have today:
Any idea on how to adjust Xert to improve the HR derived data? Thanks for your input!
You cannot compare the two activities by feeling as a technical descent can trash you when riding off-road. You may feel beat up, but you won’t have the numbers to prove that (HR or power).
The purpose of HRDM is to estimate a level of TL without power data. Too low is better than estimating too high. The goal isn’t a one-to-one match.
You can fiddle with the RHR/MHR settings under Account Settings, Profile tab if you want to recalculate the results.
On the flipside do an Internet search for “how accurate is Strava’s estimated power?” and you’ll find many say it varies substantially and is unreliable for training purposes.
Obviously 4 bpm is incorrect. My actual resting HR is an order of magnitude higher than that. I opened every single activity for the past 2 months and plotted the HR for each. I found maybe 6 rides with short drops to maybe as low as about 50 bpm. The vast majority of the HR data seems just fine - certainly nothing that should cause any proper calculation to come to 4 bpm as the solution.
Is there an easier way to find the Activity with the offending data other than by opening every single activity and manually clicking to graph the HR?
There are quite obviously lower and upper bounds on HR, just like for power. In fact, HR values, unlike power, could also be flagged/ignored when they don’t change after a few seconds. I realize HR isn’t used for most (all?) other calculated metrics when power data is available, but it still seems like reasonable boundary conditions aren’t being handled very well here.
Shouldn’t Xert automatically Flag/Ignore obviously bad heart rate data?
In the meantime, wouldn’t it be easy to add a way to manually flag just the HR data for an activity?
To fine-tune the algorithm to better reflect your current resting and maximum heart rate values, disable Auto-estimate Heart Rate parameters and key in your resting and maximum heart rate values directly.
As soon as you enter values and save settings XO will re-evaluate activities on file without power.
I’m on these pages because I’m upset over how restrictive “my data” is. I subscribe to training platforms to make myself better and find that occasionally I’m penalized, and I just want to make my data correct and nothing allows me to do that.
I spent 2.5 hours on a fat bike absolute slog. 8 miles uphill out of the gate muddy, soft, slow, absolute 50 rpm grind which then turned into a steady muddy sloth like drag for 2.5 hours total. An 8 mph average type of ride with most of the uphill being between 4 & 6 miles per hours. On a dry day with a 26 lb gravel bike with a powermeter I’m averaging 235 watts.
Now I’m on a studded tire 47lb fatbike absolutely punishing myself with my HR at 90% but because I don’t have a powermeter my data is being treated like I was on a rest and recovery day.
Why can’t I just edit my …repeat MY data?
However, no one will let me. It would be a much better approximation of my effort if I could simply put an average power number in. I cannot find a fit file tool that will allow me to do this, maybe fitfilerepair, but I then need MS Access which would not run on my laptop.
Its just ugh and all the while I’m thinking its my file. I created it. I should be able to change anything I want to change.
So I played about with HR to get it closer but it’s not representative of what the effort truly was. If I could figure out how to put a powermeter on a raceface crank fatbke with a 197mm rear hub I would but I have not solved that problem yet.
I’m not following how a cadence sensor would have made the file ‘better’ with a 50rpm average cadence.
I appreciate the platform and what it is trying to do which is why I am trying to make the input data accurate, I just feel I’m not allowed to.
The HR derived power won’t be very useful IME. If I remember correctly, Strava’s algorithms came up with much better power numbers from HR but it’s not easy to then make Xert use that data. I can’t remember if Strava will export it’s power estimates and all that could have changed by now anyway. Better to get a real power meter.
You could get a crank arm power meter from Stages that should work with your RaceFace axle. RaceFace Cinch axles are the same as Cannondale Hollowgram.
Thanks for the reply. The struggle was finding hollow gram arms and then I need to ensure that it makes it past the chainstay. (Only 8mm clearance with the race face arm) I contacted power2max months ago literally like last October and after some back and forth with them, they just stopped responding. Like crickets. I sent 3 follow up emails and not even the decency to just say we don’t want to help you.
It distresses me that they still got my money because I would love to tell power2max to f themselves with their lousy service.
However out of this, I found a place called power meter city and they are absolute top notch, fantastic to deal with, ultra responsive including writing back on a Sunday even when I asked a question, and I am happy I gave them my money even if it was for a power2max ngeco. Josh at power meter city said it should fit and it did so I’m all set on that bike now. Finally.
