Why We Test Lactate Threshold - Part 4

Revised Model of Performance - As we have seen both VO2 max and economy affect the lactate threshold (LT) but the LT does not affect the two other variables. Thus, the model of performance presented above needs to be changed. Of the three original factors, the one that most affects endurance performance is the lactate threshold. Athletes and coaches may not think of it this way, but the purpose of most endurance training is to improve performance at the threshold.

A high percentage of the training of an athlete is trying to affect these two factors that drive the lactate threshold. Few question the value of trying to raise ones VO2 max and proper biomechanics is a major emphasis for nearly every training program. But we know of no one who will say that this is all there is to it.

Is There Another Factor?

So there is a problem. Economy and VO2 max do not explain the threshold completely. This has been long understood and most training literature will acknowledge this. But most never discuss just what else affects the threshold, only that the threshold affects performance. Thus, the model is missing an important part of the picture. The above model is a more accurate one than what was originally presented, since VO2 max and economy affect the threshold. But it is missing something. What is it?

What would cause the lactate threshold to change while economy and VO2 max remain the same? What would cause VO2 max and the lactate threshold to go in different directions, which happens sometimes? The answer is quite simple. Look no further than what produces lactate. If the problem occurs because lactate and other metabolites are rising, then what is causing lactate and these other metabolites to rise.

The answer is the anaerobic system , which is rarely considered in exercise physiology and sports training for endurance events. One reason the anaerobic system is rarely considered is because it is very difficult to measure. The other reason it is not considered important is because it provides relatively little energy in an endurance event. However, it can be assessed through lactate testing and sometimes by other means. But it is not as easily measured as VO2 max. The effect of the anaerobic system on the lactate threshold has been in the literature for over 35 years but has essentially been ignored.

Given the above model, it becomes essential for the endurance athlete to measure the lactate threshold periodically, but it also is important to assess all the variables that determine the threshold because if one wants to improve the threshold one has to train those parts of one's physiology that determine it.

A better model of what is happening is in the following chart. This is derived from the work of Alois Mader and Jan Olbrecht. It expands on the model in the previous chart. It also separates what is happening in the body from what the athlete actually encounters in a race. The following model is meant for endurance athletes only such as triathletes, road cyclists, marathoners or cross country skiers. A more general model that includes short events will be presented after the discussion of the endurance athlete. This more general model applies to the Ironman who takes more than 8 hours to finish a race and the 50 m freestyle swimmer who takes about 20-25 seconds to finish the race but the model below is only for distance events.