Discussion: Load calculation/diagram

I thought that after almost five years, I knew AP pretty well. Just now, I discovered (to my delight) I've been mistaken: some athletes (e.g. Jagge) have a column named "load" in their log, and an extra diagram above the usual one (for training volume) as well.
As a (former) physicist, I'm a sucker for metrics, so how is it calculated? What do I have to do to get it in my log as well?

Load and daily TRIMP (training impulse) values in the graph are calculated here as:
minutes_in_zone_5 * zone_5_load_factor +
minutes_in_zone_4 * zone_4_load_factor +
... etc for all zones.

In that graph you can also see long (~6wk) and short-term (~1.5wk) exponential moving averages of trimp. So you can think of fatigue as your current load--that which is recent enough to make you tired--and fitness as the load you have been sustaining long enough to be mostly adapted to. Freshness is just the difference between those two. Hover or touch the graph to see the numerical values, though keep in mind that the units are arbitrary and relative. To see the graph for the current week, just click from the horizontal bar graph lower on your log.

To enable this on your own log, you have to set your own load factors via "Settings" > "Edit Intensities & HR zones" > third column. This is a bonus/upgrade feature so anyone who doesn't see this option can fix that by donating.

As far as what load factors to set, you may want to start with 0-5. I have personally set 0, 0.1, 0.2, 0.3, 0.6, 0.95 based on my own usage of intensity zones. You don't need to overthink this part initially, if you dive into the science below you can see that the original researchers got good results with just 3 categories and weights of 1,2,3.

Former physicists and curious types will enjoy some more background on the performance modeling here and here.

Thanks, Ken, that is really helpful. I now remember wondering what the extra column in the HR zone prefs was about...

I hadn't noticed this feature before. Very informative...

This is cool. I'm wondering if it makes sense to have the factors activity specific? At similar heart rates, a three hour bike ride and a three hour run may do the same thing for your cardio system, but the load on the skeletal muscles will be vastly different. (I suppose one could achieve the same thing simply by changing what a "2" means on the bike).

Can't say I've ever considered doing a "2" on the bike, so I'm not sure what it means. Aren't you worried about the back wheel?

Is this feature still available? I've set my own load factors in "Intensities and HR zones" but no graph is appearing on my log?

It doesn't show on your main log - but if you hit the back arrow (left of the graph) to the previous week you will see it (and then forward again to current week). Or set the date & range in URL to see a specific period.

https://attackpoint.org/viewlog.jsp/user_4678/peri...