Power at Lactate Threshhold vs. Functional Threshhold

I have a few questions around Power at Lactate Threshhold and Functional Threshhold. How closely related are they?

I have a bike lactate test planned for this Thursday using a computrainer. The protocol for the test is the FaCT test. It can be found here for those that are interested... http://www.fact-canada.com/Fact-Info.html

Should the test provide me with roughly the same wattage figure as some of the FT testing protocols (e.g. ave watts from 2 x 20 min multiplied by 0.95)?

I would imagine that the two a correlated but how closely? If they can be significantly different, is there a flaw in basing a training program on Power at Lactate Threshhold vs. Functional Threshhold?

If anyone can shed some light on this or point me to a thread where this is covered (I searched but gave up after 20 minutes of not finding my answer), I'd really appreciate it!

Thanks,
Pad

http://www.cyclingpeakssoftware.com/.../threshold.asp

Lactic threshold is lower than functional.

I can ride for at least 90 mins at 115% lactic threshold.

Friel defines LTHR as the heart rate you would ride at for an hour / 40km TT. If you're riding for 90 mins at 115% LTHR, I think most would say you need to readjust your LTHR. Pg 40, Table 4.4

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Cycling Blog - Training with Power

The usage of Lactate Threshold in training has been discussed with WarrenG and Andy C several times. How I'd conclude the discussions:
-The definition of "Lactate Threshold" is open. For someone it means the 2 mmol/l, for another 4 mmol/l etc.
-The definition of "Functional Threshold Power" means the power one can maintain for 60 minutes. The lactate concentration might be whatsoever during the 60 minutes.
-Wether you base your training program on some LT, how you keep your lactate level stable? OK, if you stay in the 2 mmol/l levels, and in the 120 Watts as the test group you referred, but I doubt that level will result any great improvments for your cycling. Or, like the test group; by keeping the lactate at 4 mmol/l, the power would drop from ~300 W to ~250 W during a 15 minutes interval. This is quite different approach from e.g. the basic 2*20 min intervals where the power is kept constant.
-Wether you define your training effects by power, you can keep your eyes constantly on the power meter (but sometiems have a look forward, specially if riding on road...) and keep the power levels reasonable close where they should be.

Friel uses the average heart rate during the last 20 min of a 30 min effort to define heart rate at "lactate threshold".

No scientist would refer to the exercise intensity corresponding to a blood lactate concentration of 4 mmol/L as lactate threshold - that's OBLA (onset of blood lactate accumulation).

I think you're misunderstanding the 'FACT' test (which is just a fancy acronym for a means of determining the lactate minimum).

The FACT test is really one form of the lactate minimum test, which in turn is a convenient way of estimating maximal lactate steady state intensity, which in turn essentially corresponds to functional threshold power. IOW, you should be able to use the power value 'straight up' as your functional threshold power, i.e., no correction or adjustment should be necessary.

PS: Just to avoid further confusion from developing: no one has proposed using 2 x 20 min x 0.95 to estimate functional threshold power (and I don't endorse using 1 x 20 min x 0.95 as a method, even though some people use it).

What do you endorse? (just to refresh us all), thanks!

Could you define scientist?

I've seen some material on Pubmed where blood lactate concentration of 4 mmol/L was refered as being lactate threshold. I don't like that neither. But I think it's a fact.

Why does the FACT test work as a correlation to FTP whereas a normal lactate test (ramped erg, etc) doesn't seem to have much use (based on my experience)? I guess I'm not understanding the different test protocal.

Thanks
Justin

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Just a kid riding his bike, and living his dream

Lactate threshold occurs when one sees a 1mmol increase in lactate over baseline levels. If you are in decent shaope you can hold this for a few hours. It certainly is not FTP or power that can be held for an hour. The lactate levels here are much higher.
Some guys(minds and muscles) can tolerate a lot more lactate build than others by the way.

Should I change that to "no self-respecting scientist"?

Seriously, I would assume that most people publishing in the field of exercise science/physiology would be aware of the difference between LT and OBLA. If you can point to a reference indicating otherwise, I might be able to ascertain the reason for the authors' unusual use of terminology.

By definition, maximal lactate steady state (MLSS) represents the exercise intensity at which the rate of lactate release into the circulation is exactly equal to its rate of removal, such that blood lactate concentration remains constant (or quasi-constant) over time. As it so happens, this corresponds very closely to the maximum exercise intensity that can be sustained for a significant duration, and so if you're relying on blood lactate measurements to prescribe training intensities, MLSS (and not LT) is what you really would like to know. The problem, though, is that accurately determining MLSS really requires multiple laboratory visits to progressively narrow down the precise intensity. The lactate minimum test was therefore conceived as a way of getting around this problem, and consists of performing the standard incremental exercise test with sampling of blood to measure lactate shortly after first elevating blood lactate via a preceeding bout of high intensity exercise. As a result, instead of rising exponentially with increasing exercise intensity, blood lactate falls progressively during the early states of the test, until it achieves some minimum (hence the name "lactate minumum test") and then increases again. That minimal point is the point at which lactate removal just equals lactate release, i.e., the same point (at least in theory) as identified when testing to determine MLSS.

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