Home > Uncategorized > Lactate at threshold doesn’t predict performance

Lactate at threshold doesn’t predict performance

December 27th, 2011

I was at a conference on fatigue a few months ago where one of the speakers was Mike Lambert, a well-known sports science researcher from Tim Noakes’s group at the University of Cape Town. One of the questions at the end of his talk was about the use of lactate monitoring; his answer was something along the lines of “We refuse to measure lactate, because we don’t believe it offers any useful predictive information.” As a result, the UCT sports science unit doesn’t do much work with certain teams like the South African swim team, because the swim coaches are convinced that lactate testing offers important feedback.

A new paper just published online in the European Journal of Applied Physiology reminded me of that discussion. Researchers in Austria performed a whole series of difference incremental and maximal tests on 62 volunteers to look for patterns. The basic finding was that the amount of lactate in the blood at “maximal lactate steady state” (MLSS: the point where you’re producing and clearing lactate at the same rate) isn’t correlated with how fast or fit you are.

This isn’t the first study to make this observation. But previous studies have used relatively homogeneous groups, which makes it hard to determine whether lactate levels really have an effect. With VO2max, for example, you can safely bet the someone with a VO2max of 75 will perform better on any endurance task than someone with a VO2max of 35. But if you take a group of people who all have VO2max clustered between 60 and 70, then VO2max becomes a very poor predictor of performance.

In this case, the study subjects ranged from sedentary (with 0 hours per week of sports or exercise) to very fit athletes training up to 24.5 hours per week. Their power output on the bike at MLSS ranged from 100 to 302 watts. But despite this wide range, it was still impossible to predict anyone’s power levels by looking at their lactate levels at MLSS.

So does this mean Lambert is right and lactate is useless? Not necessarily. It just means that a single lactate measurement in isolation is meaningless: you have to make repeated measurements and track your progress relative to your personal baseline, in order to eliminate the effects of individual variation.

  1. Jack Sasseville
    December 27th, 2011 at 16:33 | #1

    I would hope by now that everyone would have gotten the message that lactate in not bad for you and that all you can really use lactate measuring for is as a bio-marker that primarily tells you how much glycogen that you are using for fuel. Lactate is partially burned glycogen that is a fuel that can be used in the muscles and the organs and is reconverted in the liver to glycogen.

  2. December 27th, 2011 at 18:17 | #2

    “We refuse to measure lactate, because we don’t believe it offers any useful predictive information.”

    I’m confused. Isn’t this actually extremely valuable information? Wouldn’t you want to know this for each individual athlete, so you can properly set target paces and efforts during training? Otherwise, what are you left at to set an athletes training plan to? ‘Dumb’ heart rate formulas like 180 – Age, etc?

  3. Scott
    December 28th, 2011 at 00:48 | #3

    Other than verifying a well understood physiological relationship using a non-homogeneous subject group, this study doesn’t seem to add much to the current body of knowledge. Any physiologist or exercise scientist worth their salt knows that it is power output or speed that will determine performance. Be it AnT, LT2, Critical Power, MLSS, MAS or MAP it has been shown time and time again that power output or speed at these points is the determining factor in performance. Why the investigators would have hypothesized that it would be any different in their subject population is beyond me.
    Of more interest would be to see how each subject’s lactate concentration / accumulation changes from one test to the next at the same workload. Is it the same every time or does it change from test to test? If there are differences, what does this tell you about an individual’s nutrition, fatigue, training history etc…..?

  4. alex
    December 28th, 2011 at 01:40 | #4

    @Scott: “Other than verifying a well understood physiological relationship using a non-homogeneous subject group, this study doesn’t seem to add much to the current body of knowledge.”

    That’s precisely what they were trying to add: confirmation that the lack of relationship holds in heterogeneous groups. Their secondary stated goal was to look for sex differences (they didn’t find any). As you say, it’s not an earth-shattering result: any physiologist or exercise scientist would have predicted exactly what they found. That being said, many athletes and coaches are neither physiologists nor exercise scientists, so the finding bears repeating!

    @Brett: Good question about why Lambert is skeptical about the value of monitoring lactate. I’m not entirely sure, to be honest — I didn’t have a chance to quiz him about it. But here’s a quote from one of his recent papers (which also ties into @Scott’s second point):

    [quote follows from Borresen and Lambert 2009]:

    The inherent inter- and intraindividual differences in the extent to which lactate accumulates during exercise are two limitations of many in the use of lactate to prescribe exercise intensity. Extraneous factors such as ambient temperature and dehydration may influence the interpretation of lactate measurements… Exercise duration, intensity and the rate of change in exercise intensity may also influence lactate concentration, as may prior exercise, diet and muscle glycogen content. [24,27] Exercising with damaged muscles has also been shown to cause an increase in lactate levels. [27] Improvements in training status as well as overtraining have both been associated with decreases in maximal and submaximal blood lactate concentration, [28-30] which may lead to erroneous interpretations of lactate measurements and incorrect exercise prescription. [27] The interpretation of lactate concentration may further be affected by sampling and measurement procedures such as the time and site of blood sampling, measurement techniques and dilution volume. [24,27] The extent to which the abovementioned factors affect the way lactate accumulates, independent of exercise intensity, makes the importance of the lactate threshold less definitive, [26] thus limiting its usefulness in monitoring and prescribing training intensity.

  5. alex
    December 28th, 2011 at 01:45 | #5

    @Brett: Oh, forgot to add:

    “Otherwise, what are you left at to set an athletes training plan to?”

    Well, there are many different schools of thought. Personally, I used effort as the ultimate guide throughout my career. I don’t necessarily go as far as Lambert in saying that lactate is useless — it may well be very helpful to athletes in certain contexts. But I’d strongly argue that it’s not necessary to successful training.

  6. Bman
    December 28th, 2011 at 03:13 | #6

    I agree with Alex a fair amount, because I think that it is important to understand the concept of lactate to train properly for anything other than a pure sprint (and actually it is somewhat important in a different way for the training of sprinters), but actually measuring it may have less significance.

    Having said that, 99.9% of what I read about LT threshold training is over-simplified to the point of being erroneous at times.

  7. Andrew Webber
    December 28th, 2011 at 10:33 | #7

    Not surprised to see swimming in the first paragraph, we swimming coaches love lactate testing, and we often base all our training on it. Not me but, /keeps reading….

  1. December 31st, 2011 at 16:52 | #1