Lactate Testing - Data and Results

Nice test!

I also have been using Dfa-a1 for a few years now for cycling and running and it works out quite nicely for me. The data point lines up with my lactate testing and RPE. But I use 0.8 as my threshold since it fits my numbers better and 0.75 is an upper bound based on a data set.

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Retested and not quite sure what to make of the results when compared to the two previous tests.

If I plot out HR alone, it’s apparent fitness has improved. Lower HR for same efforts.
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However, things get interesting when I plot out LT values over previous tests.

NOTE: It’s clear the 9th value at 6:22 pace / 9.4 mph is invalid.
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Also, It’s now even more obvious the January test values were impacted by not following the exact same protocol used in December. (TLDR: I skipped earlier stages in the January test)

My takeaway is my LT1 improved from test to test however my LT2 readings are unclear to me.

LT1
December 139 BMP @ 7:53 min/mi
January 138 BMP @ 7:35 min/mi
March 139 BMP @ 7:03 min/mi

LT2
December 155 BMP @ 6:49 min/mi
January 152 BMP @ 6:49 min/mi
March 148 BMP @ 6:35 min/mi

For reference, here are the graphs for the three tests.
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Any/all feedback and observations are welcomed. TIA

LT2 is always unclear. It’s not actually clear to me that LT2 even exists. MLSS exists, but that is a different test. Take home - don’t worry about LT2 from these sorts of lactate test protocols.

Looking at your heart rate and the slight change in lactate concentration from 8:34 pace to 7:03 pace between the December test and the March test, I would conclude that your training program is having a positive effect.

LT1 in March looks to be shifted to just under 7:00 pace which is nice work indeed.

I would keep doing what you are doing. Your endurance running efforts (eg HR and Lactate at slower than 6:20 min pace) looks to be coming down and that should be a sign of building fitness. When you turn to speed work or race prep should be in good shape. Am sure you can feel that with RPE and general sensations when running below race pace.

Is that a typo in your tabulations for LT1 and LT2 in terms of months? Should it be December - January - March and not December - January- December?

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I appreciate the response… I’m going into the final block for London and was hoping the results would be a bit different (better?) but such is training. Will take the results to help inform the last few weeks to prepare as best as I can.

Its also great to take a step back view how things have progressed even if we don’t always feel it in the day to day.

You’re right, typo. Fixed.

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That probably sums up every athlete’s view toward their training and results!! It’s a good sign to never be content :slight_smile:

December to March probably isn’t long enough to see a change in “threshold” power or running pace. If you are already in good shape, and have trained for a relatively long period, it becomes very difficult to move threshold up and see a change. RPE and HR at that effort or lower look to be heading in the right direction so I would be pleased with that result and feel good heading into the event.

My experience when training well is that while my FTP didn’t bump up much, with good training diligence I could still improve other metrics and improve race day performance.

What I see with solid training is that my RPE and HR at threshold decrease noticeably and my TTE at MLSS goes up. In lactate step-testing, at sub-LT1 levels I’d see a solid 1.1 - 1.3 mMol and the LT1 point would keep moving closer and closer to MLSS. For MLSS testing, things stayed about the same in terms of lactate concentration, but it became easier to ride at MLSS (RPE and HR). RPE being a qualitative mental measurement and HR being quantitative and physiological.

I’m suggesting that you are seeing something similar. Your race pace (surrogate for MLSS) might not be improving drastically, but you are likely feeling that race pace is easier. If you’ve been doing endurance training for a full marathon, that is a great result and should point to a good race day.

Good luck with London Marathon and hope it goes well.

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Thank you - I appreciate the insight and perspective. We all easily get hyper focused on one thing or metric and lose sight of the bigger picture.

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Other than that I think for amateurs, whose overall range is much smaller, better to do 20w steps max, not sure.

Why did you only provide numbers up to 200w? What were the readings for 225, 250, and 275?

Nice graphs. Good work. Do you mind sharing your google sheets/excel file?

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Thanks. It’s quite basic but sure.

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Thanks!
I’ll share mine once I’ve made adjustments to suit my protocol

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I have read through the article and would like to try it out on my partner. Which device is the best/gold standard for home use?

Typically for home testers in the USA market the choice has been the Lactate Scout or the Lactate Plus devices. The vendor Lactate.com sells both along with test strips and other supplies.

These devices, or prior iterations, have been tested and there are some academic publications characterizing the performance of the devices. The two brands above were both fine for home use.

I’ve recently seen ads for a device called EDGE Blood Lactate Monitoring System. There is discussion of this device on Reddit. I have no experience with this device.

For home use, I’d pick a brand of test device where I can ensure a supply of test strips. The brands that have been around for a while also are easiest to get supplies for.

For lancets, you don’t need anything special. I suggest single use disposable lancets with a retractable needle. I typically purchase the McKesson brand safety lancet. It is useful to keep a few different gauge lancets on hand. Some days you need a bigger needle to get a good drop of blood.

Probably the biggest variable for home testing is getting a good blood drop and a non-contaminated sample. There are instructions up thread on how various people do this. As a self-tester, I finger prick myself and have a protocol that works. Earlobes work if you are testing someone else.

Have fun and post results to share.

Darth

I had some wonky results today. I guess LT1 at 180w maybe but the spike at 200w and then bad results after that is odd. I use FTP of 300w outdoors based on 60 min power test and quarq spider. Indoors is much harder for me, outside can cruise endurance at 210w but inside that is hard work. Max heart rate is 194.

December 21, 2024
Indoor tacx neo with 10 min steps
Watts Lactate Heart Rate
150 1.4 120
160 1.3 120
170 1.2 129
180 1.3 135
190 2.5 142
200 4.1 146
210 1.9 152
220 1.2 154
230 1.3 158

Test is fauled, should do another and test the equipment

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Aaron,

Those data points showing high lactate at 190w and 200w and likely at 210w are aberrant. There is essentially no condition where you would be at 1.2-1.3 mM (as expected for low power compared to FTP) then spike to 4mM and then go back down again while increasing wattage.

Looking forward, consider the following to improve your lactate test results and usefulness of the data:

Step zero: Establish how close the power meter you use outdoors relates to the indoor unit. No two power meters will ever match perfectly, but you should have an idea of how close they are.

Step one: Revisit your testing methods and procedures. How you are taking the sample and ensuring that a sample is not contaminated. Am assuming you are taking your own samples by getting off the bike? That is fine. Just take the sample and do the point tests the same way each time. If you have a helper, ensure they are as consistent as possible.

In the future, if you see an aberrant data point, either ignore it and keep going, or resample.

Step two: Repeat your test. You can consider a different protocol and starting point. My feeling is you are starting too low and taking far too many samples. 10w steps are fine when you get close to the LT1, but poking your ears or fingers from 150 to say 220 watts with an FTP of 300w is a lot of sticks for low utility.

With an outdoor FTP of 300w, your LT1 I going to be much, much higher than 150w. I would warm up, establish baseline and then take samples every 20-25w. See where your likely LT1 is. Come back a few days or a couple weeks later and then do smaller steps in the LT1 area to lock it down.

Something like this: Warm up 20 min. Start test. Samples at 150-175-200-225 then 230-240-250-260-270-280-290-300-310-320

That is still a lot of sticks. But next test you can adjust as you’ll have a good idea where your LT1 is.

LT1 will be where you see the consistent upward inflection start. With additional training it should shift higher and closer to your FTP. Note - I prefer MLSS to FTP when talking about lactate testing.

For LT1 estimation, I typically ride at least 5 min at each power level where a sample is going to be taken. MLSS is a completely different protocol. There are notes up thread should you wish to do that type of testing.

Finally, if you have a true FTP of 300w outside and 210w inside feels like very hard work, something is wrong. There are a few things that could be happening there and you’ll want to investigate:

First is that the power meters are giving you very different data outside vs inside. Please check this as it’s important to your training.

Second is you might be overheating and having a heightened sense of high RPE indoors. There are tons of threads on heat and indoor training and perception of indoor training feeling much harder.

Third is you might have an RPE to Physiology disconnect. Your perception is real, but it’s mental and not physical. This is one place where lactate measurements can help an athlete improve. If your legs are good (low lactate measure at a certain power) but your brain is screaming, you can work on the brain part.

Despite what coaches will tell you, not all athletes have well calibrated RPE meter built into their brains. many do but some do not.

TL;DR - Establish the relationship of your outdoor power measurement to your indoor power measurement. Repeat the lactate test trying to be as consistent as possible with sampling. Determine the cause of your indoor vs outdoor RPE disconnect.

Very best luck,

Darth

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I suspect my tester or strips are faulty because:

  1. I’ve done this same protocol before and gotten valid results
  2. I did this test twice recently and bad results both times
  3. In between these two tests I bought new test strips and calibration fluid and still bad results the second time
  4. Whenever I got a bad result I did more hand washing and repeated measurement and got another bad result, I just didn’t put the multiple readings at each power level in the results for simplicity
  5. I have someone else taking the readings, they are very consistent and it worked fine last time prior to the recent two tests

I probably won’t do any more lactate testing because I don’t want to buy another lactate tester and have the possibility of junk results again.

On the power difference, it’s something I’ve struggled with for years and never figured out, TR always is dismissive and says 1 FTP works for indoor and outdoor which is false for me. I have quarq spider power meters and assioma pedals outdoors so 2 good ways to tell what power is. Indoors is a tacx neo, can take 3% delta for sure is only 10w for the difference between measuring at crank vs at rear cassette. I have plenty of cooling, I have 3 fans that I usually have on the lowest setting because otherwise I’ll be shivering while wearing bibs. My left leg does 55-60% of the work. I have a 1cm longer left side either due to hip rotation or bone length, tried shimming under right foot but doesn’t change anything except causing massive back pain. I think the trainer just applies resistance totally different to outside, feels completely different on my legs. I will mention in the past I had a year long period where I pretty much only rode indoors and then my indoor and outdoor were very similar, seems I have to train my muscles for using the trainer.

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Hope somebody in here can help me out a bit.

I just got my first lactate test ( results in the bottom )

My lt2 i read as around 260? I think this number is a bit low (of cause :slight_smile: ) - my ftp on TR is 300, and tested ramp test in zwift of 310 ftp.

So i am in a bit of a confussed mind : where should i focus my training? Should i just do 260 as ftp? ( this is right now is my low SS - just did before a 3x15 min @256 and also did 3x8 min at 300.)

Hope somebody can explayn this to me - am i just good at keep going at high lactate?

Results:

Watt Laktat Max hr RPE
160 1,5 144 1
180 1,4 150 2
200 1,5 163 3
220 2,1 168 4
240 2,4 173 5
260 4 181 7
280 5,4 185 8
300 10,3 190 9

There are dozens of different defintions of LT2 (LT1 is better defined). You can’t compare FTP to LT2, this is an apples to oranges comparision. FTP may correlate with LT2 but is does not necessarily match up. And as said before, there are dozens of different defintions for LT2.

Your lactate shoots up quite a lot in the end. Bring the curve down by building your base.

I ran your data through Lactate-E http://www.uiginn.com/lactate/lactate-e2.html. It’s free (if you have access to Excel) and based on a published paper…and pretty useful.

These are the values from the spreadsheet. I used a simple graphical method for estimating the thresholds.

I estimate between about 215-225 for LT1 and between about 265-270 for LT2.

Which values are the “correct” values is for you to determine. :slight_smile:

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Soo… where should i ride in the zones.