Threshold Pace is too Fast

Well, wrong (as to be expected).

Knowing zones very well does not mean to use or favor them for high intensities.

Well the efforts are supposed to be hard but an uncomfortable hard. You can kind of tell if its over or under threshold just be seeing if you need to bend over and put your hands on your knees. If you need to do that then it probably means your around 3-4 mmol.

Wow lexel. You could have answered his question and enriched his understanding in about the same amount of time you insulted him. Classy.

One way in which low lactate would present itself as "progress" when instead it's more likely the result of fatigue is the role glycogen plays in blood lactate levels. In a low glycogen state, which would be the case if you're depleting your muscles with regular hard workouts, lactate levels will not rise as high. What would look like an improvement in your lactate curve is actually the result of glycogen depletion/fatigue.

So yes, high lactate levels would mean you are running hard for a session, but in your case, the lower lactate levels that produce a "right shift" in your curve, combined with what would likely be a low value on the max test, would suggest you've overdone it in one direction (aerobic capacity) at the expense of the other direction (anaerobic capacity).

Also, Crapgame wrote a great post and suggestion for what to do.