To me Lactic Threshold is the max speed where there is still a state of balance
with acid lactic production and its cleaning. Around 4mmol but that point can
be higher or lower than 4mmol. Beyond that speed the acid lactic begin
to accumulate in the muscles.
Usually a well trained runner can sustain that speed for 50 - 60 minutes.
So for an elite long distance runner LT speed is Half Marathon speed.
For other runners can be 15 k race speed.
For others 12k or even 10k.
Jack Daniels coach always remember that if you want to improve a function
you need to stress that function ,So in this case train at the exact pace of
the LT not faster or slower. Others coach they give a more generic definition
or better they give a wider range of pace where you can train your LT.
Anyway Threshold workout every week is ok.
And this of course depends from the event you are training for.
Example if you train for an HM. Threshold runs or Threshold rep. are very
important cos the speed is near to HM speed.
But of course is important for all other event . If we improve our
Lactic Threshold automatically I will improve my Marathon speed.
But also 5k speed and 10 k speed.
Of course I need also to train for the other event but just to say that
everything is connected.
I like the approach of coach like Steve Magness that use to put emphasis
on one type of workout during 6-8 weeks but at the same time not forgetting
the others types of workout.
Example you can do 6 - 8 weeks where your main workout will be LT
so once a week you will train LT. At the same time but not every week
you will also train the other speed .like Vo2 max (3000- 5000)
repetition at 1500 pace , hill sprint etc.
Than in another phase thing will change and the focus will be on Vo2 max
while others type of workout will be done less frequently.
The meaning of this approach is TO NOT forget what has been builded
before in the training.
As Coach Canova always said is not that an athlete loses his speed cos
he s doing long runs . He loses his speed cos he has stop to train it