Posted: December 9, 2004

Running: The "How" and "Why" of Lactate Training

Excerpt from Chapter 6 of Lactate Lift-Off - The "How" and "Why" of Lactate Training by Owen Anderson

Not surprisingly, scientific research reveals that fairly intense training is the best booster of lactate threshold (LT). But before we get into this research, we should mention that another popular method for raising LT - doing a lot of training at an intensity which produces a blood-lactate level of 4 mmol/liter - is a very questionable practice. 4-mmol training became popular, especially among swimming coaches, about two decades ago when it became apparent that a reading of 4 mmol/liter was at - or slightly above - lactate threshold in a fair number of endurance athletes. The basic idea was simply that by training "at the limit of the lactate system" (e. g., at the "lactate threshold" of 4 mmol/liter), as it was often expressed, one could increase the chances of strengthening the "system" and boosting LT.

This is very tenuous thinking, however. For one thing, a reading of 4 mmol/liter is not really at the limit of the lactate-producing system; in fact, it is often the point at which lactate appearance in the blood really begins to take off. It's not even the limit of the "lactate-containment" system, if you prefer to think of the threshold in that way, because lactate clearance is actually much more dramatic at higher exercise intensities and blood-lactate readings. It's just that lactate production is so lofty at the higher intensities that the expansive clearance rate can't quite keep pace, and so blood-lactate readings tend to rise.

Another problem with 4-mmol training is that many athletes can exercise very comfortably and without apparent fatigue or stress even though their blood-lactate levels may be at 6 or even 7 mmol/liter, well above the 4-mmol mark. These stable, comfortable lactate readings (of 6 to 7 mmol/liter) indicate that these athletes have not yet reached their LT, even though they are well above the 4-mmol "threshold." Attempting to boost LT by training at the intensity which coincides with 4-mmol/liter lactate concentrations would be foolhardy for such athletes, since they would actually be training below LT - and thus creating too weak a stimulus to propel LT upward.

That being said, we should note that 4-mmol training can improve LT in some athletes, specifically in those who reach LT at a lower lactate level, but it is by no means the best way to produce a really impressive LT, even for those athletes whose LTs are below 4 mmol/liter.

As mentioned, scientific research strongly supports the idea that intense work (at and especially above LT) is best for hoisting LT. In a study carried out at the University of North Carolina at Greensboro, runners who suddenly raised their average training intensity by completing two fartlek sessions and one interval workout per week boosted lactate-threshold velocity significantly in just eight weeks and as a result shaved more than a minute from their average 10-K times. The fartlek work involved two- to five-minute bursts at 10-K pace, which is about 2- to 3-percent faster than LT speed; the intervals were completed at about 5-K speed, which is usually around 6-percent quicker than LT velocity.

The idea that intense workouts are best for raising LT was even more strongly reinforced in research carried out at York University by Stephen Keith and Ira Jacobs. In the York investigations, one group of athletes trained exactly at LT, a very popular form of LT training, for 30 minutes per workout. A second group of exercisers divided their 30-minute workouts into four intervals, each of which lasted for seven and one-half minutes. Two of the intervals were completed at an intensity above LT, while the other two were carried out below LT. Each group of athletes worked out four times per week for a total of weight weeks.

After eight weeks of training, the two sets of athletes achieved similar increases in VO2max and LT. The gains in LT were impressive, averaging 14 percent in both groups. Advances in aerobic enzymes were also notable - and nearly identical in the two groups. In an endurance test in which group members exercised for as long as possible at an intensity which corresponded to their pre-training LT, the above-LT athletes seemed to hold an edge, sustaining their exercise for a total of 71 minutes, while the at-LT subjects lasted for 64 minutes.

At first glance, these results seem to suggest that there is not much advantage to be gained by surging through highly demanding, above-LT workouts, but wait! If you have been following along, you probably noticed that the above-LT athletes really logged only 60 minutes of quality work per week (4 X 15 minutes per exertion), while the at-LT subjects put in 120 weekly minutes of quality exertion (4 X 30 minutes). To put it another way, the above-LT athletes achieved the same gains in LT and VO2max as the at-LT folks (and perhaps enjoyed a slight advantage in endurance) - with only half the total quality-training time. It is reasonable to assume that had the above-LT athletes stepped up their volume of above-LT work a little bit, they would have outdistanced the mundane at-LT trainees quite easily.

To purchase Lactate Lift-Off, please go to RRNews.com.

Posted with permission from Running Research News and Owen Anderson.

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