Determination of Lactate for Threshold

[Splash]

I am going to be tested in a lab next Feb for my LT (among other things) for cycling.

After that, I want to conduct my own LT testing periodically (with a portable lactate analyser) to determine my progress of fitness level.

To do this, I need to test my blood lactate concentration whilst on the spin bike (controlled environment, settings).

What is the current industry practice position in agreeing on a set blood lactate concentration to signal the onset of the LT trigger point (reflecting the last point where lactate entry into and removal from the blood are balanced) ?

I do understand that everyone's LT is different, but I have read some literature with the following outcomes representing most of the population:


1) when lactate levels reach 4 mmol/L blood.
http://www.ucdmc.ucdavis.edu/sportsmedicine/resources/lactate_description.html
http://en.wikipedia.org/wiki/Lactate_threshold

2) the point at the work rate which blood lactate level exponentially increases
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769631/


There may be other viewpoints, but I need to know what is this magical trigger point for blood lactate concentration.

Thoughts?

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[Joachim]

Unless you are completely untrained, your HR at lactate threshold won't change that much as your fitness progresses. The one thing that does change and the way to measure fitness progress, is your power output at lactate threshold. So unless you have power data with your tests, it really won't help you to do frequent lactate threshold testing with HR only. If the spin bike has power, they are often inaccurate. Something like a Computrainer is much better.

[Splash]

Thank you for the reply.

Yes, I agree with your with all of your comments.

If speed is used to accurately (as best they can at least) determine LT for runners (who are not equipped with a power meter), is there any reason why cyclists (without power meters connected) cannot use speed for accurate regular testing of LT as well?

What other measures (besides HR and speed) can be used to assist in establishing increased accuracy of LT and conducting training sessions around LT (without a power meter)?


Still keen to learn what this magical trigger point for determining LT blood lactate concentration level.



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[gasman]

I had LT testing done several years ago when out of state. When I got back home I used a fairly flat road to see how far I could ride in 8 minutes at threshold ( warmed up and similar road conditions wind, temp etc). That is still my measure for fitness. I use a HR monitor as that's all I have but when I'm finished with a training block and feel fit I can always go further than when I'm not as fit. It's cheap and may not be super accurate but it's been good enough for me.
Besides nobody pays me to race and I just quit racing this year.

[Splash]

Thanks Gasman.

Good info. Did they measure glucose and Vo2 max as well (if so how did you utilise that data)?

Did you change your intensity after you had your LT tested in the lab?

What do you think you are missing out on by not using a Power Meter?

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[Splash]

All,

Attached are 8 pictures showing lactate curves (lactate vs HR) I found in a document that dug right into LT training, etc.

These pictures show real data from real athletes. Each curve tells a unique and interesting story about the particular level of fitness for that athlete.

For each curve, I want to know the single value of Lactate is (by referencing the vertical and horizontal axes) which represents the Lactose Inflection Point (or LT). The referring document does not state them.

interested to read your opinion to learn what you think each Lactate value is for the LIP or LT for each curve in each Figure.

This information will greatly assist towards the answer of my original question.

Let me know.

[shovelhd]

You don't need blood work to determine LTHR, but it is by far the most accurate. Standard testing will be sufficient to determine training zones.

[mike p]

This...A hrm, a ten mile TT and some serious motivation will be more than good if your goal is to establish training zones. To check on progress repeat TT under like conditions.

Mike

You don't need blood work to determine LTHR, but it is by far the most accurate. Standard testing will be sufficient to determine training zones.

[wasfast]

The lab method may be the most accurate (at a given point in time) but it's certainly not the most useful. You also need to understand what you'll use the LT number for. It's really a value for a given amount of time, commonly for a 1 hour effort (40K TT). It doesn't help you much at all for, say 15 second sprints.

Speed is really the worst option as there are too many external factors that can cause large swings. Things such as aerodynamics, rolling resistance, wind, etc.

HR has a reputation for not being very accurate as it too is influenced by other factors day to day. My own LT is about the same no matter what training level I'm at. My power level though, will vary.

Power (watts) is by far the most common method these days. You can read "Training and Racing with a Power meter" by Andrew Coggan and Hunter Allen. They use 1 min, 5 min, 20min and 60min power levels to show where you stand across the spectrum of needs from long steady efforts to sprints. They also have an excellent table for w/kg to show where you stand in power against beginners to Tour Pros.

A power meter allows you to field test any time you wish and lets you use flats or climbs to do so.

The lab tests are interesting but rather expensive and not very useful day to day.

[Splash]

Thanks Guys.

WasFast - Are you able to voice your opinion on those 8 figures I attached earlier - in relation to specifying where you think the LT point (lactate value) is located for each lactate curve?

Wary about the expense of those power meters :-( but I know I may need to succumb one day.....what PM do you have on your bike?

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[HenryA]

I think a few things:

You are trying to use a micrometer to measure a 2X4 when a tape measure would be appropriate.

A large number of readings as you suggest would be useful over a relatively long period of time to show a trend, but not that revealing as to each event measured.

Your LT level is not that trainable, and probably the smallest detail to manage. Knowing that you had a bad week at work and are stressed out or getting a little extra rest in your schedule might be more valuable in real life day-to-day training.

A watched pot never boils.

Finally, if you are going for the world hour record next year, ignore everything I wrote above.

:)

[shovelhd]

There have been many recent threads on power meters here. Dig around, it won't take you long to find them. On the race bike I have an SRM. I bought it used for a grand. On the rain bike and for backup, I have a Stages. I bought it used for $500. There are many low cost options available today and more are coming.

While it is true that training with power is more efficient than HR only, you don't need a power meter to start structured training. You can set zones with HR and train to the zones. Just don't be looking for incremental increases by the numbers as HR is influenced by many things and is not as stable a metric as power.

[Splash]

Thanks Shovelhd.

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[shovelhd]

No problem. Sorry I can't help you with the graphs.

[Mark McM]

The graphs show a lot of data, but that isn't really useful unless you know what it means. (This seems to be a recurring theme now that many fitness measurement instruments are readily available to cyclists, such as heart rate monitors, power meters, etc.)

There is unfortunately no universally agreed upon definition of where the lactate threshold is. Is it a blood lactate level? Is it a rate of change in the lactate level? And to make matters even more confusing, blood lactate values can vary wildly from one individual to the next.

Some years ago, I took part in a study on the physiological parameters that best predict uphill time trial performance. The researcher used a sample of riders who had recently finished the Mt. Washington Hill climb bike race (7.6 mile long that climbed 4,780 feet up Mt. Washington, NH) and measured a variety of physiological parameters of the subjects. Included was a test on an ergometer in which the subject rode at a periodically increasing power output, while measuring heartrate, expired CO2, and blood lactate. I did the test with a friend who was a similar size and age as myself and had a similar finishing time in the hillclimb. His blood lactate level at the highest power output that he could continuously maintain was 4 mmol/l, and when the power output was increased, his lactate level spiked to 8 mmol/l at the point he could no longer continue. Conversely, at the power output I was able to continuously able to maintain my blood lactate level was 8 mmol/l, and when the power was increased to the next level my lactate level spiked up to 14 mmol/l. Clearly, my friend and I could not use the lactate level numbers for training purposes.

[Joachim]

His blood lactate level at the highest power output that he could continuously maintain was 4 mmol/l, and when the power output was increased, his lactate level spiked to 8 mmol/l at the point he could no longer continue. Conversely, at the power output I was able to continuously able to maintain my blood lactate level was 8 mmol/l, and when the power was increased to the next level my lactate level spiked up to 14 mmol/l. Clearly, my friend and I could not use the lactate level numbers for training purposes.

That's is a good example why power output at a certain lactate level will be used for training purposes, not the lactate level itself. Its all dependent on the data of the individual. That's why I use both the (power and HR) data from lactate threshold and OBLA (onset of blood lactate) for the riders that I coach.

[gasman]

[QUOTE=Splash;1675314]Thanks Gasman.

Good info. Did they measure glucose and Vo2 max as well (if so how did you utilise that data)?

No neither was measured.

Did you change your intensity after you had your LT tested in the lab?

Changed my workouts my adding weekly intense intervals.

What do you think you are missing out on by not using a Power Meter?

I have had to use HR only as a basis for my workout zones. HR is so variable that a power meter would have served me better but I was too cheap to spend the money as I raced for fun.

[Splash]

Thanks guys - very good reads.

Joachim - How do you use both the (power and HR) data from lactate threshold and OBLA (onset of blood lactate) for the riders that you coach?


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[sworcester]

I had this done a few years ago, but basically shows you the data that came back.
VO2 was done on a different day if I recall correctly.
Setup was my bike on a trainer that had settable power levels (I think)

I can't post an Excel file, so it is zipped

I don't think there is any copyrighted or personal info in the file

[Splash]

Thanks Steve.

Interesting data.

What was your LT base don this data and what is 'CHO'?

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[sworcester]

Thanks Steve.

Interesting data.

What was your LT base don this data and what is 'CHO'?

Splash

Honestly, I don't know. I hired a coach from no baseline, I just wanted to get better, or at least know my baselines for training. From the tests I learned where I would burn the most fat and be able to stay in a heart rate "forever".

I do train with a power meter but use it afterwards, maybe not the best, but the on bike data was too erratic and I got chided for burning the match too early. Heart rate is too suseptable too sleep issues, work and everyday efforts but seemed to be a better baseline for me. It also told me when I was over training or getting sick. I don't race (although I did that year) but wanted to know where I was.

[wasfast]

Thanks Guys.

WasFast - Are you able to voice your opinion on those 8 figures I attached earlier - in relation to specifying where you think the LT point (lactate value) is located for each lactate curve?

Wary about the expense of those power meters :-( but I know I may need to succumb one day.....what PM do you have on your bike?

Splash

I used a HRM for 4-5 years as a relative (not absolute) measure of how hard I was going. I race primarily TT's but also it's useful for climbing to not overextend in the early portions. I've used 2 different Quarq's (crank based PM) over the last 5 years.

I still use the HRM and cross correlate with the PM. Triangulated with PE, you can tell day to day or race to race, how things went. PM's are much better about keeping you honest in the first 1/2 of a race. Since HR rises slowly (minutes), you will generally go harder early on than you should. That comes back in a very bad way later on. Power allows keeping a more constant load. Your HR will (or at least should if you have the right mean Power value) be lower and then match up fairly close for the 1/2 half of a TT.

All the science is interesting but it has to serve a purpose. Realize that ultimately, these are feedback and/or measurements of your performance. Humans aren't robots. Things chance day to day for a host of reasons. The lab testing is a slice of time that may or may not be replicated. You may have had a good day or a bad day in the lab.

These are my own thoughts, YMMV:

VO2 max shows you how well you did in choosing your parents. It does improve slightly with training but not a ton. Frequent testing of it is mostly just expensive.

Likewise, my own LT based on HR is pretty much the same, I'm just putting out more or less power.

Power hits it's best usage for sustained efforts. Using it for crits, sprints, road races etc is interesting after the fact but you're usually not in control of it since you're often reacting to others efforts. It can even be a downside. If you look down and see you've been going well over your 20MP or 60MP, chances are you'll freak out. The demands are what they are in those situations. You may explode or you may just hang on. Tough to know but backing off because you are watching your PM is not suggested.

Power is useful to keep track of your overall progress year over year. There are times when you'll do a ride or race you've done before and feel WORSE or BETTER. The power file can tell the story better than remembered PE. I've been on rides where I thought guys were just tearing my legs off. Later, I look at the efforts I made and they were in fact going very hard. That's reassuring as you can psych yourself out, thinking "they're fast, I'm slow".

The thing that's interesting after using all the gadgets for some years is that you can generally know when you're close to the limit or at a reasonable percentage of it. PE can work as you get further down the road but at the start of serious racing & training, it will bait you early on and kick your butt at the end.

My own suggestion is to do some of the more standardized tests like the 20 min max effort. 60 minutes would be optimal but few want to do that, especially me. You can roughly extrapolate 60MP from 20MP by deducting 6-7%. It's useful to retest your actual threshold (with a PM preferably) every few months. Progress from training or decrease if overtired, are both useful and you can do these any time you like with out a lab and needles:-)

[Splash]

....Since HR rises slowly (minutes), you will generally go harder early on than you should. That comes back in a very bad way later on. ....

My own suggestion is to do some of the more standardized tests like the 20 min max effort. 60 minutes would be optimal but few want to do that, especially me. You can roughly extrapolate 60MP from 20MP by deducting 6-7%..

Thanks.

Is this standard in all humans (minutes for rate of HR rise)?

What is this 20 min max effort and what is 60MP?


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[shovelhd]

60 minute power versus 20 minute power. Training zones are based primarily on 60 minute power. Testing for 60 minute power, or FTP, can be done many ways. One way is to ride a 60 minute time trial. This is the most accurate but also the most difficult. Another way is to ride flat out for 20 minutes and multiply by 0.95. It's all in Coggans book.

HR climbs over time during aerobic exercise due to a phenomenon called cardiac drift.

[Splash]

Thanks buddy.

Our bodies sure are amazing machines!


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[jbrainin]

FWIW, to know one's heart rate at LT can be very useful when doing long-distance touring such as coast to coast USA rides.

Basically, keeping one's effort below LT enables one to to do five weeks worth of consecutive ~100 mile rides while allowing relatively easy recovery.

[Splash]

..is this how the pros manage to ride every day for 2 weeks on Tour-de-france?

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[shovelhd]

No, that would be EPO.