Confused by Lactate Threshold test results

many problems here, both conceptual and practical. I'll list a few.

all lactate parameters (and there are actually many) can be estimated rather well without the need for treadmill testing.

even if we accept treadmill testing as useful,the incline used in the testing you describe overcompensates for the lack of wind resistance.

your athlete was not tested properly, nor is testing actually necessary. change the protocol, get different results, more importantly, not much of a justification to

design training around this concept.

if your athlete wants to run say, 1:15 for a half marathon, she will most likely find she is chasing runners with better speed at 1', 5', 10' duration and so on, and so the issue is not so much superior fatigue resistance, oxygen delivery or blood lactate. in fact, for a well conditioned, hard working athlete, more of the same can actually be detrimental to the health and performance capability of the athlete.

to date, the best treadmill testing predictor of distance running performance is the peak running velocity, which is a nice way to say, who so ever lasts the longest is the fittest.

if you email me this weekend I can help you sort some of this out, give some alternative perspectives with which to attack in the training and point you to some useful readings.

dsrunner

dsrunner@juno.com

You are confusing lactate threshold with anaerobic threshold when refering to hm pace.

Aren't LT and AT functionally the same thing?

Were they testing vo2 during this and if they were were they testing respiratory quotient (RQ)? At what point did RQ hit 1.0? I'm assuming you just paraphrased the test results. Should be a lot more data at much more frequent intervals. If you post more it might be easier to translate.

LT -Can you provide the following information? (1) VO2 cost: both the absolute (total mls of oxygen at the end of each stage) and the relative number (mls/kg/minute) at the end of each stage.(2) Duration of stages and how long the runner stayed at the final speed (kph)(3) Perceived exertion at the end of each stage (Borg scale values, for example).Also, was the test terminal? That is, did the runner perform until exhaustion set in?Regards,Tinman

Thanks for the responses!

Wasn't testing V02 only lactate, so sorry no data there....

3 minute steps

The test was taken to termination, determined by athlete....1:30 completed at 17 kph

I think the only other data was something stating her aerobic threshold was at 70% of Speed at V02 Max and that the LT was at 87%.

I could be wrong, but it looks like they might have not actually tested for a LT but rather just extrapolated assuming LT occurred at 4MMOL. A lot of people use 4MMOL as LT. This is similar to using 220-Age as max heart rate... you might be right, but you could also be wrong too. Looks like a flaw in testing to me. I have best results using respiratory quotient of 1.0 as a fairly easy, non invasive way of finding LT. It correlates very well.

Can you explain a little more the method they would use to test actual LT rather than assuming 4mmol?

thanks!

And i assume the respiratory quotient of 1.0 is something derived from testing V02 max at the same time?

I think the question you need to ask yourself as a coach is what was the point of this test? You know what she can run a HM in and what pace she can hold for different tempo type workouts. What was this data going to add? How would the results change your training? Did you test for the sake of testing? Seems like it was a waste of effort.

LT? wrote:

Can you explain a little more the method they would use to test actual LT rather than assuming 4mmol?

thanks!

And i assume the respiratory quotient of 1.0 is something derived from testing V02 max at the same time?

The most accepted way of determining Lactate Threshold - at least to my knowledge - is to blood test more frequently than your athlete was tested and look for a turnpoint in the lactate curve. This has a tendency to occur at 4 MMOL but many athletes hit their turnpoint at under that and many over that. One interesting thing I noticed from the test you mentioned was that your athlete hit half marathon race pace at HR 181. While it's possible, my initial inclination is to guess she doesn't run a half at HR 181. This would suggest that the treadmill to outdoor speed correlation was off.

As to the respiratory quotient. Every VO2 test I've been a part of also had a CO2 expiration as part of it. When CO2 expiration is equal to VO2, that is a respiratory quotient of 1.0 . that is a great place to put threshold and requires no bloodshed!

sisyphus wrote:

One interesting thing I noticed from the test you mentioned was that your athlete hit half marathon race pace at HR 181. While it's possible, my initial inclination is to guess she doesn't run a half at HR 181. This would suggest that the treadmill to outdoor speed correlation was off.

Yeah that's exactly what I thought....because the speeds just don't match up with her track times or with her runs on other treadmills.

she mentioned that they adjusted the speed 1kph to account for the fact that treadmill running is slightly easier....I'm wondering if the doubled up the compensation because it would make no sense all to adjust to 2% grade AND subtract 1kph. I'd be surprised if that's there standard procedure but it sort of looks as if that's what they did.

Thanks for the feed back and the explanation about the respiratory quotient....maybe next time I'll find a another facility and have them test VO2 as well.

The problem with using a lactate analyser (and the protocol of 4mmol) is that you need to use this continually if it is to have relevence to further training. Perhaps (if you can find out a max HR) establishing a less invasive protocol of a HR range for that individual (say 70-90% of MaxHR)might be better. i.e. if max HR is 200bpm, then doing a 5 mile progression run of (140,150,160,170,180bpm per mile), that can be repeated at regular intervals of training, might give a better idea of LT if the pace (time/mile) is correlated with effort (HR) and racing results on similar terrain (track, road, trail, park, etc.) and conditions (Weather). 90% should be reasonably close to LT, at least it could either give you a starting point (if coming back from injury, break or whatever) or let you know whether the LT level (if assumed to be anywhere from 10k-1/2Mar RP) is above or below that HR % and so training pace can be adjusted accordingly.

without getting into the methodology of LT testing. the idea of determining the LT is to use this information to determine the HR or VO2 at which this occurs. So you can determine the LT by keeping the pace constant and increasing the grade, however this would not be that practical for running, therefore you used 2% grade and change the speed of the treadmill. it appears that the LT corresponded to a heart rate of roughly 170 give or take. you did not measure VO2 so we do not know what VO2 corresponds to LT. in order to use this information to incorporate into your training or racing of your runner. you now know that this athlete can run at a HR of 170 before the increased rate of production of lactate exceeds the removal of lactate, therefore you would want her to race at a speed that keeps the HR at or below 170. you can not interpret the speed that was used for this test since a 2% grade was used. the useful information is for your athlete to run on a treadmill on the flat and see what pace corresponds to the HR at which the LT occurred.

It seems apparent that they are using 2.0mM as aerobic threshold and 4.0mM as lactate threshold. My observations with this is that only marathon runners (or cyclist) that do much of their training under 2.0mM fit this profile. Low mileage type runners and frequent training above 2.0mM will have a different curve. It is difficult to find “aerobic” and “lactate” threshold because we are still trying to figure out how to define it. One of the newer definitions describe it as 1.0mM above baseline. With the data you presented baseline looks like 1.6-1.7mM would be baseline, LT would be 2.6-2.7mM, according to the newer definition. The problem is that training changes the accumulation, usage, and clearance. It also changes the lipid/cho reliance and this contributes to lactate metabolism.

I do however believe endurance runners should aim to fit the 2.0mM/4.0mM mold to maximize performance. I also agree with what was said, ~1.0 RER does connects very well with LT regardless of the type of trained runner. LT can be as high as 6,7,8 mM especially if maxLactate is well above 10.0mM.

With the test, I do 6-8mins because it takes at least 2-3minutes to reach steady state and it takes ~2minutes for lactate in the muscles to correlate what is in the blood. 2% maybe a little over expression but not too much. Studies have shown that 1% also correlate very well to over ground (road) running.

first off LT is a waste of time. anyone who actually knows anything about LT will be able to show you that most fit people can run faster than their LT for a given time. LT is loose correlation of capacity. The best indicator is a metabolic acidosis threshold test or the actual race time. Lactate theory is a bunch of bullshit some scientist came up with in the 60s and is way outdated. Stick to pr's in this case and dont worry about metabolic issues

Don't think run

Aghast wrote:

I think the question you need to ask yourself as a coach is what was the point of this test? You know what she can run a HM in and what pace she can hold for different tempo type workouts. What was this data going to add? How would the results change your training? Did you test for the sake of testing? Seems like it was a waste of effort.

[/quote]

BINGO we have a winner!

Jeezus, don't over think this very simple sport.

the guy can run a 1:19 half, that tells you what all the other training paces can/should be within a few clicks.

Looking at the numbers, I'm guessing that the 2% grade is the likely culprit slowing the speeds down.

Probably better to associate it with the HRs, and forget the treadmill speeds.

Or you can have her run on the track at various HRs to see if these track speeds are faster, at the same heartrates.

For all intents and purposes (for athletes and coaches) VT, AT, and LT are basically functionally equivalent. Athletes don't really need to be that exact.If you want a short explanation of these terms, here is a link from Greg McMillan:http://www.mcmillanrunning.com/training1.htmwith brief descriptions in the sidebar.

LT? wrote:

Aren't LT and AT functionally the same thing?