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Acute Training Load Calculation

I recently noticed that GC is now reporting Acute Training Load (ATL) for recent activities for my Fenix 6; ATL replaces "Training Load". GC states that ATL is a "weighted sum of recent exercise load scores".

Does anyone know the mathematical calculation for ATL? What is the weighting value that is multiplied by each day's exercise score (Exercise Load) in the process of calculating ATL?

Thanks!

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trux over 1 year ago in reply to hobdell1 +1

hobdell1 said:
So, if on Day 0 there is a load of 100, on day 1 this counts for 90, on day 2 it counts 80, etc. So, by day 10 the contribution from that Exercise Load to the Acute Load is zero.

Thanks for…
hobdell1 over 1 year ago in reply to trux +1

Okay, I have more data and a few points where I really only recorded once. I used Excel to fit the data between Exercise Load and Acute Load. I get a perfect fit but here is how. Basically I need to add…
trux over 1 year ago in reply to hobdell1 +1

hobdell1 said:
Why does Garmin increase the Exercise Load by 28% before adding to the Acute Load table????

Yes, it looks almost perfect. Thanks! With real-life data, and a factor of 1.275 instead of 1.28…

All Replies

0 profarvin over 1 year ago in reply to trux

Thanks for taking a look. I did see the power spikes in the activity from Edge but I didn't think it would make such a big difference in TL because every 30s interval avg and norm power numbers are the same for both activities.

You're probably right even though the TL diff still seems to big. One more argument for this theory is that GC shows the Edge's activity's focus as Anaerobic while Zwift's activity's focus as VO2 max.

0 trux over 1 year ago in reply to profarvin

profarvin said:
I didn't think it would make such a big difference in TL because every 30s interval avg and norm power numbers are the same for both

Anaerobic effect is triggered by short burst of high intensity, hence even very short peaks of high power just a few watts higher may result in a significant increase of the anaerobic effect. The avg. and normalized power is more relevant to the aerobic effect, and tells very little (or practically nothing) about the anaerobic effect.

And then, the anaerobic effect has a more important influence on the EPOC, than the aerobic effect, and hence the Training Load will increase significantly too.

0 DaveBrillhart 10 months ago in reply to trux

Ok I modeled your approach. My Calculated Acute Load worked perfectly for 8 days of my data, from 3-Nov to 10-Nov. That even included a big day with Exercise Load of 639 on 4-Nov. The Error (Calc AL / Actual AL) was ZERO. But on 11-Nov, starting my new ramp up of consistent Exercise, it broke. So something is wrong with the model of using a linear 10 day weight against EL*1.275. If I find the right model, I'll post. They still suggest it is a 7-day TRIMP calc, which is exponentially weights, not linear. So I'll try that.