Hi David,
oh, if I’m not mistaken you did indeed. It’s already a bit in the past. 
Maybe I should update the blog some time a bit. But then - tools evolve and it’s no news that the reader is invited to just check for himself what the current status is and if the tool is interesting for him or her. All I can do and want is to wet the appetite… 
ITI = Iditarod Trail Invitational?
Brrr… cold!
And Unbound XL - congrats. Yeah, I guess this would interest me sometime also. But going overseas for such a “short” race (lol - everything is relative, I guess) is no thing I’d undertake lightheartedly. Maybe I would incorporate it into a longer visit of the states… once we hopefully can plan such journeys with more confidence again.
Yeah. I found out about it recently and it has infected my mind… to the point that I’m mostly looking past Unbound XL towards ITI 350. Remains to be seen if I take to winter ultras–fat bike still hasn’t arrived yet! But I’m collecting the gear for it. On paper it seems like a good fit. We’ll see!
Yeah, it does seem that there’s an added challenge in that you have to do sleep dep in order to finish by the cut-off whereas in most bikepacking races you can set your own pace. We’ll see how it goes. I’m always little hesitant (almost superstitious, even) about guessing at my performance in these events.
I like Amanda Nauman’s take: “My first goal is to finish. My second goal is to win.” The first is not a given in the slightest!
This is pretty much what Xert does and I think it works well.
Each ride is analysed and work is allocated to Peak, High and Low energy systems, which are then tracked in a similar way to the CTL, ATL and Form. Peak and High are added together and tracked with a shorter window of 22 days. Low is tracked with a window of 60 days.
Xert will only advise you do high intensity workouts when your Peak + High Form is above zero but will continue to advise endurance workouts if your Low form is above -30% of your total Training Load.
Xert also balances the amount of Peak, High and Low strain in your system at any given time by suggesting workouts that create that balance.
Unfortunately the current TSS system has no way of separating those out.
Mike
Thats interesting. Do they adjust for age at all? I have found as I have gotten older (50 now) I can handle much less high intensity stuff and have tried to compensate by adding volume.
I don’t think they (Xert) compensate for age (I’m 74 so would probably notice), but they extract your “signature” from all your rides rather than doing specific tests so presumably it will have an effect. Also it’s very easy on any day to swap in an endurance ride if you need to. There is no pre-built plan, each day they suggest a workout based on your current load and your stated goals.
As @John_Dalton said, they don’t make any direct compensation for age but you can change the constants for High + Peak and Low independently for both Chronic and Acute trading load to better reflect your own recovery rates.
Mike
If I were to guess, PMC was geared towards certain disciplines where the higher and lower intensity stuff can be grouped together. But it may be that the equivalency between them isn’t a linear relationship, particularly when you get into very long distances. Doing a tour averaging 80 miles a day doesn’t mean that you’re suddenly ready for 500 TSS weeks of high intensity.
The problem with combining them is that if you’re doing a very polarized training plan, the low intensity TSS makes it harder to track high intensity TSS. Additionally, high endurance volume is more volatile–fitting a 10 hour ride into one’s schedule isn’t easy and you often have to take what you can get.