The following animation is based on an illustration in Jan Olbrecht's book, The Science of Winning. It shows the position of the lactate curve shifting as the aerobic and anaerobic capacity of a swimmer get stronger or weaker. An explanation of how the two systems interact to affect the lactate curve is after the animation. These curves are not meant to represent any specific level of capacity but range from very low to very high values of each compacity. As the capacities increase or decrease the curve changes. This is one of the main objectives of training, increasing or decreasing these capacities.
These lactate curves are based on a two speed 400 m swim test. Jan Olbrecht has conducted over 10,000 such tests on various levels of swimmers and needs only two swims to determine the shape and position of the lactate curve. Often only one test is needed if it is done at the right intensity and right distance.
This illustration is for swimming but the same effect happens in the muscles for every type of physical endeavor. The lactate curve for running, cycling, rowing, speed skating, cross country skiing or any other activity/sport will respond in the same way to changes in these capacities.
The above model indicates that there are two aspects of your basic energy metabolism that affect the lactate curve, namely
Thus, changes in either will affect the lactate threshold. And both of these capacities can be trained.
Importance of aerobic capacity - We make the comment at various places on this site that there is never enough aerobic capacity or VO2 max. We have not found any athletic situation where a lower VO2 max is an advantage. Thus, training to raise it is always an objective. We add this one very important caveat: sometimes training to raise VO2 max takes away from training that is more important for the athlete and some training to raise VO2 max can affect other aspects of optimal performance negatively. For example,
Importance of anaerobic capacity - Anaerobic capacity does not act the same way as aerobic capacity and because it is difficult to measure, little is understood about its specific effects. Just how does anaerobic capacity affect an event.That is what the anaimation above is meant to show. Here is a diagram.
Let's take a 1500 m runner in the example below. His aerobic capacity was 79.6 ml/kg/min at max during the time period measured and his best time 3:32.4. How could he become faster? From the above model, he could raise his aerobic capacity and that would definitely make him faster but it is already pretty high so that might be difficult. Not shown in the above diagram is economy of motion and if he could improve that he would also become faster. And these are the two ways that most coaches emphasize for improving their athletes.
VO2 max varied from a low of 4.8 l/min to a high of 5.6 l/min in a 18 month period which is a 16.7% improvement, hardly a trivial change. Within the first year, the change went from 4.8 l/min to 5.16 l/min. Using ml/kg/min the low was 70.5 ml/kg/min and the high was 79.6 ml/kg/min. Performance changed substantially as the runner's best time in the 1500 m race went from 3:38.9 to 3:32.4 min:s from the beginning of year 1 to the end of year 2 (3:32.94 was the winning time at the Beijing Olympics in 2008.)
So training to raise VO2 max is very rewarding. This study has several interesting aspects and will be referred to at other parts of this web site.
As the athlete's VO2 max goes up or down the lactate threshold will do the same. In the above study, the velocity at the lactate threshold went from 16 km/hr to 18 km/hr over the two year period, a 12.5% improvement. These corresponded to increases in VO2 max. So improvements in VO2 max will also affect the threshold positively.
This was later published in a journal. Here is the cite.Ingham, S. A., et al. (2012). "Training distribution, physiological profile, and performance for a male international 1500-m runner." International Journal of Sports Physiology and Performance 7(2): 193-195.
But there is a third way which might be fruitful. We do not know if the runner's anaerobic capacity is optimal for the 1500 m race. Suppose it was not and suppose it was too high. Then workouts that lowered the anaerobic capacity would make this runner faster at 1500 m. If the anaerobic capacity was too low, then workouts that raised the anaerobic capacity would make the runner faster at 1500 m. Notice we said it would make him faster at 1500 m. By changing the anaerobic capacity the runner would be less effective at other distances. If the anaerobic capacity was lowered, less speed would be available and the runner would be less effective at shorter distances. By raising the anaerobic capacity the runner would be less effective at longer distances. The two energy systems have to be balanced for the specific race. This is a topic that is not understood very well and there is little if anything about it in any training literature.
Similarly a swimmer who is extremely good at 50 m and 100 m may not be best at 200 m and rarely is a good 400 m swimmer. But by lowering the anaerobic capacity of the swimmer, which must be very high for short sprints such as 50 m, the swimmer may become an extremely good 200 m swimmer but no longer will be as good at 50 m.
One last comments on this here.
We are working on changes to this animation to make it more useful and instructive. If anyone has suggestions, send us an email: info at lactate dot com