Wait, I am confused. If your goal is 120. Start with it set to 118 and just don’t touch it until the end. That would be a more clear test. I am not sure we track HR target at this time so that makes this hard to analyze unless you keep the target the same the whole time. Sorry if this was not clear.
Ok, when you wrote “you can try lowering your target” in a message above I thought it could mean doing it even during the ride. BTW, this was the second ride with this same problem. In the first ride I did not lower it during the ride, but it was the same (no screenshot of that one unfortunately, the request came after that. But I have the fit files, in case)
@Alex What’s the algorithm you’re using to adapt Power to a HR gap?
For example: how much %FTP power-change would the app send if HR is stabilized at a value of 5 bpm lower then the target?
We know that Power/HR is a linear relation in the zone from AeT (and even quite a bit below) to AT, but the multiplier will be different for everyone.
If somehow you could first get Power and HR at AeT, it makes calculation of the multiplier easy because you already have AT and FTP from the profile. Even if this multiplier is only reasonably correct, controlling the workout from HR would become fairly easy. That is off course only for steady efforts within the aerobic intensity zone.
Simple example assuming 160 bpm as AT
- 120 bpm → 120 W
- 160 bpm → 200 W
40 bpm delta creates 80 W delta. Sending 2 W extra per bpm lower from the target should get you pretty close to target in a short time.
Send me TCX from your original, that’s probably best. What was your target in that one?
Ours is very simple and should work in this case and most cases. I don’t think I can say all the rules here without digging into the code even though I wrote it 
It starts with 40% of FTP as your initial target power. It looks at the difference of HR now to HR target and determines how much to rise. If the difference is bigger it makes a bigger increase up but with a limit of 5w I believe. So if we have 20bpm to go it might be 5w it increase every 30 seconds or 1 minute (can’t remember). Once it starts getting closer it only adjusts a smaller percent as little as 1 or 2watts of adjustment for a bpm difference of like 3%. Once it is within 2% of target it just stops. Same logic on the way down. The problem is in his example, he is above his target and it keeps increasing the power. This should be impossible.
There are other limiters and stuff but that is the basics. It’s totally basic but really should work and seems to work in most cases. Not sure what is unique here since it looks normal. I have to plug his data into our code and see what happens.
As we move to HR intervals we need logic more like you are suggesting as we need it to be able to react faster. For steady state our slow reaction time is fine and should work.
121 bpm. The TCX always from your site?
Will try it for sure within the next weeks. The weather and sunset time start to call for indoor rides during the week…
Yes TCX from our site is best.
Please do. I always appreciate your ideas and analysis.
Thanks, done
Got it. Now I think it is pretty clear what is happening. It’s not necessarily a bug but more of a refinement that is required. We allow +2% over target before making adjustments down. Also by the time you hit +2% your are on a path up that is going to higher than that.
Different peoples heart rates react at different speeds so it can take a bit for it to start coming down again.
I am pretty sure if you start a workout and set it to 115 it will never go over 121. Now there is ways to cause your HR to jump. But as you see your HR approaching target you can practice some deeper breathing. Again you may want to pedal and forget so for now setting at 115 should allow that.
Some people might be able to set closer to their limit. Now as we discuss this we should not allow +2% as most people are trying to use HR as a cap to the limit. Secondly we need some other refinements or earlier bigger adjustments when it goes over. I assumed this case would arise. I did not do a lot of testing with myself but extended testing I might see the same.
Hope this makes sense. If you could do one more test with starting at 115 and never changing it to confirm that would be ideal. We will do some adjustments to also improve this. At them minimum don’t allow +2% before lowering it.
Sure, will do a test at 115 bpm tomorrow or Saturday and let you know (here / should I send you the TCX file again? Need more screenshots?)
Thanks again
I have the same threshold of 121 HR. I’ll try too
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I’ve done the HR rides 4 times now and have a good feel for how the app responds.
I set it at 126 or 128 BPM and if the app sees a heart rate differential of ~ 4 or more off set point at 00 second or 30 second times it will adjust my power by 4 watts to try and bring the heart rate to set point.
I’ve found the algorithm is very good.
Dave
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Thanks, you can just email me TCX from our website is best.
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i have mine set at 126 and a few times i can reach 133 but the algorithm adjusts the power. i can feel it becomes easier to have my hr go down. Usually at the end of the ride my average is 125. it is working well as far as i can tell.
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I’m using the HR workout control and it is working really well after a bit of manipulation of my Threshold HR & FTP post a Heart Attack. Perfect for my needs now i have learnt to just put a final HR target in and let it work me through a warmup.
One thing that i haven’t got my head around though is the purpose and relevance of the “power target” in the box at the bottom of the screen that shows the % of your Threshold HR that you are targeting.
Is it the initial power value that is redundant at the 1st increase in resistance, or something else? I have no idea if this value changes in ride as it is too hard to read for me.
It would be good to know if i need to consider it’s value or not when manipulating the Threshold HR & FTP in settings
Power target is more for testing/understanding. Their is no real relevance in training, that is why it is so small The 60% is slighly confusing also as most people think in terms of BPM target but showing BPM target would duplicate that number. Maybe we should show % of max HR instead of % of THR but we don’t currently capture or use that number any where.
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Done again for today’s ride
Thanks for the clarification Alex
Edit: Out of interest then, what does the hard to read power value represent?
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