Problem report using HR target

Bugs and Issues
#1

I tried https://app.trainerday.com/workouts/nd2023-4-s100 workout today to test HR target. Please see the result at https://app.trainerday.com/activities/656444a198edc9bcdc26d335.

The goal was to test the HR target feature and try to see if it was possible to determine my top of Z2 by assessing my breathing for each of four 15’ periods at HR 100, 105, 110, 115.

The problem I see is that when entering an HR target interval, TD seems to always command a very low power, not using the current power/HR to adjust from there. Please Ignore the first 2 periods (I was surprised by the behavior, so manually adjusted target, changed cadence…), and just look at the 3rd and 4th where I let things adapt and kept constant cadence. You can see I finish the 2nd period at 165w stable HR 105 (which was the target), and I get into 3rd period set to target HR 110. I expected that TD would raise power immediately, but instead it dropped to about 60w. It then raised very slowly, letting HR drop to 96 pulses, and then took 8 minutes to reach HR 110 at 185w.
At the end of 3rd period, entering the 4th period targeted 5 pulses higher, same behavior happens.

Also, I noticed that when entering intervals, the new HR target was not taken into account by TD. This is maybe because I manually changed it on the 1st interval, in an attempt to try to get TD to raise power quicker. Also, when I entered the final cooldown erg ramp, the app didn’t switch to display erg/power target but stayed in HR target mode. It did still command the trainer correctly in erg mode.
I also broadcast the activity to the web app. There, it always showed target as power, never as HR.

Regarding this HR feature, I think the software should take into account:

  • current power/HR to calculate change to target from there
  • user power/HR curve to make an educated guess of what power will be needed to get to the target HR and get there much quicker.

Other than that, once the target HR is reached, power was correctly stabilized.

Eric

#2

Hi Eric there is new version that just came out (Apple today, yesterday google) which should resolve the power dropping issue. If in your workout you had put approximate power target rather than 0 it would not have not dropped so much.

Right now this is a new feature so it does not make big power jumps quickly as the primary or at least first objective for this HR feature is Z2 work and in this case it’s recommended to slowly arrive at target HR. And generally it’s considered an upper limit rather than a target, so if we immediately jump to conversion than there is a good chance it will jump over the limit not to mention most people would not accurately enter their conversion values.

We just finally got intervals working correctly as of yesterday/today. Soon we will be looking at how to improve it, which includes figuring out how to do it so jumps a little below the target power rather than very slow (every minute) increases/decreases. The problem is peoples heart rates react differently so and even different on different days as well as people having different objectives. I guess my point is I have not figured out how to perfectly target quick HR / power changes that will work for everyone yet. There is another thread on this and generally the optimal way is to determine someone’s vector projection that adjusts during the workout. We love this feature so we will continue to enhance it.

What you can do for now is if you want it to jump quickly is put in a small ERG section at your target power and it will jump fast and then will retatin that same target power and slowly adjust to HR. If you want me visually show what I mean let me know.

#3

Thank you Alex for this long answer.
I have updated the app and will test again in a few days. You say it should resolve the power dropping issue. Does that mean that when entering an HR interval without a power target, it will now stay at the ending power of the previous interval, whatever type that previous interval was? I just didn’t have time yet to test, but I’ll try.
Eric

#4

Yes that is how it is designed to work and works for us in testing but I never tried it with a zero target interval, but I am pretty sure it will work correctly for you even with zero power targets.