Stephen Sieler on cardiac drift, power/HR and so on

david · 26 April 2020 16:57

I could make it the 1st half or an hour whichever is less?

The green line is the decoupling and I thought neg decoupling wasn’t all that interesting so left that bit out. But maybe that needs to go on its own little stripe then it can have a scale and the zero line will be the 1st half/hour reference.

Or I could just plot the HR ratio itself and add a 1st half value reference line.

martinheadon · 26 April 2020 17:02

Sorry I might be being stupid, but where do I see this chart? I can’t find it.

Longest recent one I have is 90 minutes which might show up something. https://intervals.icu/activities/3064495285

martinheadon · 26 April 2020 17:04

Ignore me, found it. Was looking in the heart rate section.

Josh_Tanner · 26 April 2020 18:45

Hi David, these all have a fair bit of intensity in them, but all are just over 4hrs with mostly Z2/3 and pretty steady. Saturday is my official long ride day and unfortunately most of them are indoors lately…

https://intervals.icu/activities/3162326259
https://intervals.icu/activities/3228048498
https://intervals.icu/activities/3316269281
https://intervals.icu/activities/3350965065

Brian_Lande · 26 April 2020 21:11

David, this is a excellent new feature. It certainly helps assess aerobic base. Any chance of tracking and plotting a metric that allows for identifying changes in performance over time?

Bogdan_Rylski · 26 April 2020 21:23

@Brian_Lande Check this out:

Dane_Propoggia · 26 April 2020 23:23

3h - https://intervals.icu/activities/3348893869
2h - https://intervals.icu/activities/3291399131
2h - https://intervals.icu/activities/3301204412

Michael_Webber · 27 April 2020 00:31

david:
You have certainly sparked interest! Well done.

On the baseline: Seiler uses the second 20-minute interval because in the first power is high relative to HR, as the rider warms up. But I suppose that over an hour this would work itself out. And an hour is better than 20 minutes if this is to be used for outdoor rides too. So I think first half or an hour, whichever is less.

On the green line: I think that its own little stripe would be best. And it’s not a zero line! It’s a 1.0 line.

Brian_Lande: the key metric is the time at which the green line [Pwr/%HRR] begins to deviate from the horizontal, for a given average power output. This is what Seiler is trying to track, I think – at what point is the body beginning to be stimulated beyond what it can currently do. That seem to me to be difficult to identify in an automated manner.

Daniel_Hernandez · 27 April 2020 02:09

Wow, this is awesome! Never thought it was going to get this much attention. I love this subject and hoped you did as well, and indeed my hopes were met! Thank you!

Ray_Isaac · 27 April 2020 03:35

Just donated for the first time. The straw that broke this camel’s back is the incredibly quick response to this request. I was vacillating about whether to make a similar request but was reluctant to ask without ever having contributed.

This is a really interesting and useful topic for me, so thank you Daniel for initiating it and David for implementing it!

Daniel_Hernandez · 27 April 2020 05:22

I have many! All from 2 to 5 hours long, some very steady, some with some slight power changes:

david · 27 April 2020 05:34

Tx. Some nice rides there. Its working well on those. The ones with de-coupling the power and HR traces diverge nicely and the 2nd half has green decoupling creeping up.

david · 27 April 2020 05:36

Definitely. I already tried once but couldn’t figure out how to clean up the messy data. Going to get back on it shortly. Good ideas on the other thread.

david · 27 April 2020 05:42

Ok I will move the decoupling onto its own trace and change to 1st hour or half whichever is less. The configured warmup time for the activity is already excluded. Tx for all the feedback!

Daniel_Hernandez · 27 April 2020 05:45

I really like it so far, here’s some things to improve if possible:

Several times I have negative decoupling, but the graph is locked in 0%. Maybe good to see it too, like a line at 0 in the center.
The ending of the graph sometimes doesn’t match with the “cool down” on the slider just above. When I move it anywhere it does refresh and match, it’s just the initial one the first time I get in an activity
On long rides that I stop for 3-10 mins, the graph stops working after the break.

david · 27 April 2020 09:24

I have made some changes/improvements:

The decoupling trace now uses the power % scale (i.e. right hand y-axis)
Zero power points get a decoupling of zero which helps reduce the effect of stops and downhills. Those were getting 100% decoupling before which is obviously bad.
The “1st half ratio” used as a reference for decoupling is now the first hour (after warmup) or the first half whichever is smaller
I fixed some bugs with the warmup/cooldown not always being properly applied
The marker now moves smoothly on the chart

Bogdan_Rylski · 27 April 2020 09:41

Awesome! I noticed this was throwing things off.

Michael_Webber · 27 April 2020 09:41

Yes!

I think, David, that in your graph above your blue line is actually HR / power. Decoupling means that HR rises relative to power.

I also think that if you are using a baseline hour or half ride, then the warmup slider should not be applied to this analysis.

Do you think that the scale on the right hand axis should be smaller – eg go from 0 to 50? After all, a decoupling score of 50 would be huge: you’re either dying or barely crawling along!

Oh, and is there a global setting for resting HR? Or is that something I should check every morning before a ride?

This is really great work. Thank you.

Bogdan_Rylski · 27 April 2020 09:51

Looks much better! no effect on the decoupling from my snack and pee break.

david · 27 April 2020 10:25

The problem with messing with the right hand scale is that it is also used for power %. If I make decoupling fit a different scale then it needs its own chart or a 3rd y-axis (yuck). I like the fact that it doesn’t interfere with the main power and HR data.

You can set default resting HR in /settings, on the 3rd line of options near the top of the page.