Originally Posted by
fstrnu
I couldn't watch the videos.
The first link you posted doesn't even mention cardiac drift. I don't think that's much of a scientific reference supporting your hypothesis. It does discuss your Internal:External-Load Ratio but doesn't think much of it:
However, while practically attractive, the implementation of this approach is limited unless care is taken in controlling and quantifying the athlete’s external loads and the environment in which the exercise is completed.
I'm a little surprised that your second link is to a Friel article in the TrainingPeaks blog. Quite the contrary to what you advocate, Friel says:
So one of our goals when working on AeT is to keep decoupling to a minimum-less than 5%.
(AeT is Friel's acronym for aerobic training.) Again, this link does not support your hypothesis.
In fact, both these links support the TrainingPeaks system of using training stress and associated equations as developed by Andrew Coggan, Ph.D. Coggan's equations are also used in a great deal of other training software. The Coggan equations not only give you your current training levels, but can also be used to predict future training levels and thus to create effective individual training plans.
CD is interesting in about the same way that HRV is interesting. It's interesting, but it doesn't tell us much nor is it a good predictor of training consequences. Really. Get a Premium membership in TrainingPeaks and start charting your CD workouts there. You'll quickly see why those interested in scientific training use it or one of its many clones.
The first article to which you linked has a nice chart toward the bottom which I was happy to see. It shows a sweet spot and a danger zone for ATL/CTL ratios. The top of the sweet spot is at a value of about 1.25, which is exactly the same as what I've observed in my personal training as an effective upper limit on fatigue. Everyone loves to have their own findings confirmed.