First of all we have to look at what you need in terms of real conditional capacities.
Lactate thresholds have been used to asses one's endurance capacities related to many sports such as cycling, running or swimming.
What you are asking is basically if you can improve the delay in onset of lactate accumulation that is correlated ( not cause ) with the aerobic-to-anaerobic energy system transition.
Problems of the thresholds
We must understand first of all what we are referring to when we talk about LT ( Lactate Threshold ). For exemple, your wikipedia extract is not precise in describing effectively what Lactate Threshold is or are.
85% of %HRmax and 75% of VO2max are still only general measures that are based on general indications aswell; these measures have been shown to coincide with the anaerobic thresold in some, but not all individuals (expecially adv. athletes ) and I'm not going to take these indicators in consideration.
To focus only on LT, there are two thresholds.
The first one is called Aerobic Threshold (AT), and the second one is called Anaerobic Threshold (ANT) ; even for the AT there is a general observation that put it in correlation with the 50% of VO2max.
The AT is considered the upper limit of the exclusive aerobic mechanism usage ( this doesnt mean that glycolysis does not occur ), while ANT is considered the upper limit after which the anaerobic system become more and more consistent and the body relies more on a glycolitic/fast type metabolism.
So what we want is to consider ANT to answer your question.
Yes you can improve your ANT
There are several protocols of training for improving ANT. On top of that a big body of research over the years has accumulated work that shows how the ANT can be found at different lactate concentration in blood ( ranging from 2 up to 10 mmol/L )[1-2].
This however do not correlate with performance. When you improve your ANT you actually have a shift of this limit upward thowards the exerted power ( it means you can exert more power and sustain more intense workload without the accumulation of further lactate.
This happens because you have improved your aerobic capabilities, but I won't get in depth in this argument just because it would lead to an enormous Off Topic.
How to improve your Lactate Threshold (ANT)
It largely depends on your sport but the key thing you have to keep in mind is that you must target what you need.
You can perform in two different ways.
- Training your CVS ( cardio vascular system ) or Central Training: This is done by putting volume in the equation; just accumulate volume following a linear fashion periodization ( high volume that will decrease over time ) and at an intensity slightly lower than ANT.
You can actually also follow a Non Linear periodization style, but this is really up yo tou. The key is to actually accumulate volume that will lead to central adaptation of your CVS at a slightly lower intensity than your ANT.
- Training your muscles enzymatic capacity and overall buffer capacity or Pheripheral Training: this part of the training will lead your body to broader adaptation in your muscles. You will build more oxydative enzymes like SDH ( succinate de-hydrogenase ), crucial in oxydative metabolism. You will develop more capillaries and more mitochondria in the muscle.
This is just a brief sum of the anatomical adaptations. This type of training is performed at slightly over the ANT for prolonged periods of times.
So basically this is it. Periodization advices could be given more in depth if your objective was more specific and in relation to a known sport.
How to asses ANT
There are plenty of tests to asses the ANT. The main problem here is actually the sport in which you perform. For cycling you want to use a cyclo-ergometer, but for running there are plenty of field tests.
Take in consideration that you want to asses the correlation with speed/power and the time it takes to reach exhaustion.
Here some good indication on some tests.
