give some numerical examples, because as post above... everything seems arbitrary

the same person can have different definitions ......

For 15km to marathon-distance runners, Pfitzinger prescribes tempo runs of four to six miles at 15km to half-marathon race pace.
For marathon runners, he recommends up to nine miles at between half-marathon and marathon race pace, or a 13-mile run followed by five miles at between half-marathon and marathon pace.

but he is giving a fair description what he means , ie the description is more important than the term.

which is why i dont really care what people say they are doing but care what they actually do and what method they use to define a certain amount of precision to what energy system they want to train ie having a robust calculation ie such as a lab test and for lt1 the talk test which is reliable race data and not using just one parameter such as power, hr or rpe but at least 2 or 3. and then still operate in a certain range depending on how you feel.



your zones are different pretty much everyday so even if you have everybody to speak the same language you need to have a system that can reliably calculate your stress in training , outside training and sleep quality and motivation, mood , weather , altitude , health status and your nutrition divided by general nutrition and fueling of the session. and we are just not there yet, and while its good that we are working on it the now overmarketed so called scientific methods as modern coaching is still nonsense. paolo sousa wrote a nice article on that a while ago what scientific coaching means atm.

and nothing wrong with easy, medium and hard as long to take into calculation your power profile, the distances you race and train and what level you are and the environment. so you do need to individualize what easy moderate and hard you need.

The problem with running word basing tempo on miles is terrible. 15k tempo can be 90 min for slow folk and 45 min for top runners. Huge world of difference. Biking world based on time

And of course even on the bike they can be huge differences
As 20 min theshold will impact a beginner that might have a strong anaerobic engine as he comes from football or soccer might struggle o much more than a guy that has been to the olpmpics in triathlon Vs an 30 times ironman.
At the end you have to find out what works for the individual.

Something I hadn't even thought about that may be worth mentioning here. I haven't seen any research on it but honestly haven't looked to hard either.

Cycling and running threshold, by most accounts is either 60min max power/pace or MLSS. We know MLSS is slightly different than 60 min power, and different for different people in different ways. But are those differences similar on an individual between cycling and running?

That is to say, my MLSS is ~310w and my 60min is ~325. My running MLSS is ~6:10 and my 60 min is ~5:50. That's a 4.6% difference in cycling and a 5.3% difference in running speed. But a huge difference but hardly insignificant. Nowhere near the 85%/95% difference cited by OP.

I guess I'm just curious if anyone else has worked out these numbers, and if it may (partially) explain the difference in traditional "tempo" workouts. Idk maybe this is entirely nonsense too.

Because he was using his Z3 bike power to define "tempo"

This is what I've done. I purchased the 80/20 books and a few of their programs in TrainingPeaks, so now I'm married to these zones.