Further to my above post I think there are other mistakes of factual and theoritical nature on this thread:
A. The "treshold" training done by the Ingebrigtsens is NOT anaerobic training. It is their most intense kind of aerobic training. As stated above they make sure that the lactate number isn´t higher than 3.1-3.2 which is significantly below the treshold to anaerobic training. So it is a bit misleading - in my opinion - to call it treshold training.
When talking about long runs: The Ingebrigtsens´"treshold" training equals the rather fast long runs (= tempo runs) for other runners.
The Ingebrigtsens NEVER run fast long runs. The use long runs as recovery training.
B. Some people here are talking about Jakob running 100miles per week. As far as I remember from a recent interview he runs 185km per week which is 115 miles.
C. Someone was talking about the very long runs where the slow twitch fibers gets depleted calling the subsequent activity anaerobic exercise. I think this is also a mistake.
What happen is that the rarely used fast twitch x fibres take over which actually should improve the runners sprinting abilities. This has been described by my first running hero the late Peter Snell who himself benefitted from the "Lydiard Boys" ´s famous sunday Wiatarua long run at 22 miles on mountains roads. He was from the beginning told by the more experienced runners that he "would loose the best part of it" if the didn´t finish the whole 22 miles (35.4km) long run.
Snell in his early thirties initiated an academic career in the US where he gained a B.S. in "human performance" and later a Ph.D. in "exercise physiology". In his academic career he among other things verificated most of his former trainer, Arthur Lydiard´s, theories about running, including the beneficial impact of long runs on the sprinting ability. Snell was himself a superior finisher dominating completely the middle distance running in the first half of the 1960es.
From Peter Snells Wikipedia page:
"He (Peter Snell) gained a B.S. in human performance from the University of California, Davis, and then a Ph.D. in exercise physiology from Washington State University. He joined University of Texas Southwestern Medical Center at Dallas as a research fellow in 1981. He was associate professor, Department of Internal Medicine and also director of their Human Performance Center. A member of the American College of Sports Medicine, Snell was honoured in 1999 as an Inaugural Inductee, International Scholar, into the Athlete Hall of Fame, University of Rhode Island".