Kryten
good link - the critical part about the paper in relation to the base conditioning phase - and it is important that this phase is studied in isolation is "So in conclusion, after considering the arguments of both Maffetone and Hadd, I can see no reason for avoiding moderate amounts of running near or even above the lactate threshold during the conditioning phase, provided excess cortisol production is avoided."
Now I don't know about you all but I have difficulty determining lactate threshold tolerance level from HR never mind when the body may or may not be producing cortisol !!!
Periodisation in training is important and if a base phase of steadily increasing mileage of 12 weeks or so is carried out without exceeding lactate threshold levels except on occasional bits up hills etc then the aerobic system efficiency will be maximised.
Thereafter increasing quantities of higher threshold training may be introduced and this will benefit both aerobic and anaerobic systems. But getting the foundations of aerobic conditioning right in the first place enables that subsequent phase to be successfully undertaken with less stress.