Should cross training be figured into your weekly CTL?

Cycling has been my only form of training for the last 4 years. I recently started rock climbing which I enjoy a lot and do 2-3 times a week for a total of 3-4.5 hours. I am definitely noticing that I don’t have as much energy or ability do same amount of TSS per week as when I only rode my bike with no other cross training.

My question is, since climbing can be somewhat quantifiable by heart rate data (even though maybe not super accurate) is that something I should log in to my training calendar for a better assessment of fitness / fatigue?

To me, it depends on why you’re tracking CTL/TSS. If you’re mostly using it to track overall fatigue and freshness, yes, figure it in. If you’re using it to track bike training load (or if you have a training plan by TSS), than adding the climbing would obviously distort that and you’d have to leave it out. Figuring in the climbing if you haven’t previously would also mean you can’t compare your current CTL to last year’s, for example.

However, to me the most valuable information I get from those measures is how fatigued I am, so adding all the crosstraining would make sense.

You could also maybe test it and do both - use two different programs that track CTL (or maybe create a second account somewhere?) and add climbing in one, but not the other. And then see what makes more sense to you.

To answer your question, technically climbing can be quantified using hrTSS but the colleration with bike fatigue and fitness is weak. Even on the bike, TSS doesn’t always tell the whole picture.

In my experience, asking myself how I’m feeling on the bike or at the gym, has been more valuable. You could look into other measures of readiness like HRV.