So…what’s your “real” LT? 
ETA:
With 210w = 1.4 and 250w = 1.4, I wasn’t seeing a breakpoint in there. Could take the 220 to 230 going 1.1 to 1.3 as a break point but that 0.2 increase was only possible because 210 to 220 dropped from 1.4 to 1.1.
One way to interpret the results is the lap duration vs rest duration might be allowing the readings to drop or not stabilize to an accurate value. Doing longer duration at each power level might find LT1 clearer.
Risking confusing matters if you plot lactate & BF against HR you get this
In my limited experience these threshold are not single points, much as we’ed wish it, but rather small ranges.
Based on how I feel and how hard I can push the pedals, I’m thinking around 220 watts.
I mostly ride to RPE, so collecting metabolic data is more an exercise in collecting data at this point.
Thanks. I’m collecting data just to have the data and casually monitor progress. Metabolic testing is a fun hobby. I’m not following any training program other than maintaining a slow progression to more volume. I decide how hard I’ll ride any day based on how I feel waking up.
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I think I want to play with this during the next winter….What lactate meter brand is recommended?
Edge?
Scout?
Plus?
Thanks!
I only have experience with the Plus from lactate.com. I’ve purchased two sets of control solution and probably 12 boxes of strips and haven’t had any real issues to speak of. I use my meter at home and at the track primarily and make sure I use the control solution based on the user manual recommendations.
I also buy the single use lancets, but I find them wasteful.
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i have got one of these. I dont know where you are in the world though so dont know if the website is applicable.
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Same experience and vendor as Garage Lab with the Lactate Plus. Colleague who is a coach has used a Scout for many years with no issue. For home use, I’d choose the meter for which you can reliably obtain test strips for at a decent price.
I also employ single-use lancets and keep a few different sizes on hand.
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Thanks @GarageLab @DarthShivious and @carytb
I’m asking because it appears that there are some meters with biases in the low/high end of La spectrum.
With caveat that I’m not a proper analytical instrumentation expert, I do recall looking at this publication when I started down the lactate rabbit hole. I just gave it a quick re-read.
The “bias” discussion is interesting, but I think the authors were looking for something to discuss. I tend to look at the numbers in Table 5 and 6 (std dev and %CV) and Table 7. The SD’s and %CVs look pretty good to me.
My interpretation of Figure 7 is that the handheld “field” meters yield very similar curves to the laboratory instrument. I don’t understand why cycling curves match better than rowing curves.
Table 7 - my interpretation is that for LT1 and LT2 calculations in the cycling data, all instruments were “close enough”.
The authors note that their testing used venus blood samples. Highly unlikely that any of us at home testers are going to use Venus blood. I suspect the variance introduced by finger / ear sticks will be far more relevant than the instrument variability the authors are showing.
TL;DR - The handheld devices look good enough to me in comparison to the laboratory grade instrument. The authors seem to agree in their conclusion. I feel the discussion of “bias” was an effort to have something more interesting to say than the obvious conclusion that these instruments are all fit for purpose.
Happy testing and look forward to seeing your data when you get going.
-Darth
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In my limited experience with these types of devices (consumer medical devices), there will always be trade-offs with performance. For most people, the readings will be good or close enough, as Darth mentions.
Here’s what the Lactate Plus manual has to say:
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Found this guide useful:
The only thing I’m changing is the length of intervals, would like to do something closer to the ISM protocol.
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First lactatetesting with my new Lactate Plus.
LT1: 193W, 1,1mmol,
LT2: 288W, 2,7mmol,
Not sure why my LT1 would be so low, but had a little high readings at rest and at warmup.
Did also wear a Moxy sensor, but will try doing 5-1 protocol instead of 6minutes continous riding next time.
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Thanks for sharing the data.
I’ve never been able to find LT2 with lactate testing. LT1, however, is not as difficult. Your data points are a bit wide to pin down LT1, but it is definitely not 193w. LT1 is where you start to see an accumulation of lactate up to about 1mMol increase over baseline. Based on the data shown, accumulation is starting somewhere between the ~210w data point and the 240w datapoint. If I were looking conservatively, would put your LT1 at about 230w. If being less conservative, perhaps 240w. If using LT1 to set a training power level, I make the error toward being conservative.
Should you want to home in more precisely on LT1 (no need to, but if you want to), would do another test with datapoints at: 150, 175, 200, 220, 230, 240, 250, 275 watts. Would expect to see flat around 1.1 - 1.3 mMol for the 150w, 175w, 200w, 200w levels and then a slight increase to 230w, another slight increase to 240w. Predicting around 2mmol at 250w and additional higher, maybe 2.6 or 2.7 mol at 275w.
Make sure you are doing a long warm up and ideally without too much food intake prior to testing.
Enjoy,
Darth
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The “threshold” itself is not important, you can figure out the ballpark with RPE. The key thing is to be able to track the movement of the curve overtime……provided you are organized and can control for:
- Fatigue, Sleep
- Temperature
- Hydration, Food Intake
- Cadence.
Old
That particular definition is the one we’ve been using in this thread, with examples of real world results and utility for about 4 years. Feel free to enumerate a better definition and how you would use it to help people improve.
This thread has been remarkably positive precisely because it is about people generating data and using their data. Not arguing semantics or degenerating into a pissing contest over definitions or if lactate testing is useful or not. I’d like to see it stay that way.
Thanks for your contribution.
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Hey Mark, there was an interesting discussion and anecdata around LT1 and endurance riding in Empirical Cycling’s July 9th podcast “Ten Minute Tips #29: Training Myths, Part 3: Volume”
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I listened to it. In fact it’s one of two podcasts I listen to regularly now (the other being Inside Exercise). Kollie often has good insights, and I love his passion and commitment. But he also has strong biases and perspectives.
With regard to the oft used term of “anecdata”, my perspective is that despite all the noise about “science” in cycling, what we basically have is a collection of anecdata. There are some good practices, a lot of “it depends”, and a lot of art. Which translates to trial and error at the individual level. Given my professional life (which you know about but I’m not going to broadcast publicly), am fairly confident that my opinion on what makes for good data has some merit.
In context of this thread, it’s been fun to see what people are doing and how they are using a common and available test. I think as a group we’ve been pretty clear about when it’s helpful, when it’s not, limitations and substitutions. That’s a pretty big win in terms of discussing a contentious topic with passionate people on the internet.
Somewhere up above, am admitting to being too lazy at the moment to search it out, I concluded for myself that the lactate experiments were fun, I learned something and applied the data to improve myself and helped a couple friends improve too. One by quite a bit. In that semi-summary post also noted that we could have done all of it without lactate. But the data helped and in context of what we do for the hobby was easy and inexpensive.
That said, I think lactate testing has limited utility and wouldn’t push it on anyone. But once someone decides to make the plunge am all for helping them find better protocols and such. That’s what I hope this thread continues to be about.
Something like that.
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