It kind of is already accounted for in the intensity factor isn’t it? I 100% agree that technical descents are significantly more grueling than road/gravel descents. It’s like having to perform 2-20min sets of split squats at the top of each climb, but it’s not a Training Stimulus in the same way as power generation.
Are you looking at it to gauge/measure fatigue from a ride? Or in terms of fitness gain/training stress?
Yeah, I understand. I find it hard to quantify MTB stress in terms of TSS and equating training stimulus week to week. In terms of fatigue, I find that I can relate the IF to the amount of fatigue I’ll have after a MTB ride.
Plan on a bit more fueling and recovery for hard mtb days, not sure how to quantify that beyond feel and listening to your body. Maybe shoot for a slightly lower weekly TSS over-all if you’re concerned about your MTB rides taking you into the red especially if you’re new to trail riding. I also use a PM on the MTB and I do weigh those rides a little higher in terms of time needed to recover. When I see a high TSS on a MTB ride I just know that I typically respond best with an extra recovery day/ride the following week.