Tracking the "right" Difficulty

I see that I could do a week of training and hit my Ramp Rate and Focus goals. If for example, I was on a Training Status of 3 stars, I could hit both without actually doing any 3 star Difficulty workouts, especially on Endurance weeks.

Is there anything in the Xert model that indicates the effectiveness of a period of training based on making your hard days hard (hitting Diff targets)? Does it actually matter?

As a separate comment, it might be cool to see peak Difficulty, or number of minutes at or above target Difficulty per week, as something you could monitor over time.

Generally, we don’t see Difficulty Score as a training target per se but see it mostly as a gauge that allows you to compare efforts. Generally, the more trained you are, the greater the difficulty you can handle. One thing to keep in mind though is that difficulty is uni-dimensional whereas fitness/performance is 3 dimensional. It combines everything into one metric.

I’ve been leaning more towards counting XSS along each system and how that compares to each system’s training load (low/high/peak). So if a workout has a High XSS of 15 but my High Training Load is 5 (and I’m recovered), I might find that workout ok.

If you look at the polarization rule of 80/20 from a daily workout standpoint (which is how we are looking at it), you’d do 1 high intensity workout every 5 days. So if your High Training Load is 5, you’d need to do a bit more than 25 High XSS every high intensity workout to maintain high intensity training load. That’ll likely end up being a difficult workout if you aimed to complete it as part of a regular training routine. If you want progressive overload on your high intensity system in order to raise HIE, you’d need to do much more than 25 every 5 days in order to raise it. That’s a pretty difficult workout to complete, hence the phrase “Go hard on hard days and go easy on easy days.” is the best path to follow. Going to 66/33 or 50/50 polarization actually makes the workouts a bit easier, but progress is slower as a result … a bit counter-intuitive. Doing intensity every other day (50/50), for example, makes it grow slower since you’re not able to go that hard and accumulate that much high XSS. If you decide to push real hard every other day, you can do this for a short period (overreaching) but if you kept at this too long you might start suffering from overtraining.


That part I have trouble following. Yes, the frequency with 50/50 is higher. Therefore is the volume (amount of high XSS) lower per session. So basically smoothing the high intensity efforts out over the week. I can’t back this up now, but my gut feeling tells me, that the smoothed out variant is easier to recover from.

“Real hard” = “Doing 5x your High TL every other day”, for example.

Yep, I think that makes sense.

So, you know you’re getting “enough” Difficulty because your hitting your RR target AND your Focus is shortening. If you were hitting your RR target, but not getting enough Difficulty, your Focus would stagnate. Does that sound right?

That’s another way to look at it.

One thing to always keep in mind is that training increases your fitness and your ability to express it. Two athletes might have the same signature but if the race has repeated 5 minute power efforts, the athlete with more High Training Load will have done more of the efforts in training (why they have more High Training Load, by definition) and will be better able to repeat them and more likely to do them to their limit. The concept of durability in the most basic sense is training load. The more trained you are, the better your numbers but also your ability to go deep repeatedly improves.

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Sure, after just one of these I am unsually not doing much of anything the following day.
Therefore, my point was, why not dividing this high TL by 5 or 7 and stretch it out over the week (aka. increasing frequency)?
Same training stress, less acute fatigue, open window effect, infection risk, etc.

That’s the same as going from 80/20 to 66/33 polarization. While it’s ok, the sustainable ramp rate is slower.

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For my understanding, is that from a mathematical point of view, or also sustainability from a ‘real world” physiology (or psychological) perspective?

Would your view be different for a short training block to peak for an event, vs a longer term sustainable plan?

The evidence suggests that the math and the physiology align which implies that the deeper the fatigue the faster the recovery. Doing less allows you to recover sooner but not quicker and therefore doesn’t allow you to do ramp up as fast.

Short term, you can dig a bigger hole but you need to eventually allow sufficient recovery both to avoid overtraining but also to ensure you’re doing quality workouts.

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Hmmm… :thinking: not quite sure what that means

Evidence implies the rate of recovery is faster when you go deep.
Go shallow and you recover sooner (less to recover from) but at a slower rate.
Sorta like pressing your hand into a memory foam mattress.
Springs back faster the deeper you press. :smiley:

Yeah also find the words a bit tricky but think I can follow the math, which is why I asked if it was just math or somehow linked to reality earlier. It is to do with the exponentially weighted moving averages (EWMA) used for tracking training load and recovery load (with form being the difference between them). The higher the recovery load (I.e. the deeper you go), the more it improves in an absolute sense each day thereafter. It is also not linear.

For ‘high’ energy systems the recovery load time constant is 12 by default, so each day recovery load is basically 11/12 of what it was yesterday + 1/12 of what you do today. When you recover each day, your recovery load is 11/12 of what it was yesterday (you recover by 1/12, said another way), so the higher it was yesterday (the deeper you went), the more it improves each day. But then each subsequent day it improves a bit less (only 1/12 of the previous day again), so it’s not a linear recovery, more following a curve. If you are not going deep, you’re at a shallow level of the curve where recovery is ‘slower’ (1/12 of a small number) even if it doesn’t take long. That seems to be the main reason going deeper less often (vs going a little deep more often) supports a higher ramp rate (of high TL) over time… as Armando stated above