MLSS Test: Result #1 of a planned series


Most of you know what MLSS testing is so won’t clutter with details here. For those not familiar, FasCat Training has a nice post on the topic and web search will turn up numerous articles on the topic.

Background: Myself and several buddies are gearing up for “serious” runs at 40km TT PRs and/or USA Masters National and/or the New Jersey Time Trial Series in 2019. All master’s age athletes age 50 to 75, well trained over several seasons. We are all avid time trialists trying to eek out every fractional gain possible from training and gear.

Because I’m a data dork, decided to invest in a hand held lactate meter to really track my training and offered to do the buddies too. A bunch of us (4-5 total) are going to do MLSS testing at regular intervals this season to see how we do and if having these data helps in a meaningful manner. A side benefit is if you know you are going to test a lot with a peer group you want to do well. A bit of social accountability works wonders.

Today’s Post: I’ve had MLSS and LT tests run before but always as the testee not the tester. To get a feel for running the tests and using the meter prior to conducting runs on my pals, decided to run an MLSS protocol on myself. Not perfect as one needs to pause to take the sample, but might as well make data. Plus, wife wasn’t available.

Method: Created a four step protocol in Trainer Road (search MLSS in the workouts if you want to use it). Ramp warm-up then four ten minute bouts increasing 10w each step. I estimated 230w MLSS for myself and set the interval percentages for 210-220-230 watt steps. A fourth interval of 240w is added just in case I was too pessimistic (answer = nope). At five min spacing I would pause the workout, hop off trainer and do a lactate test. Each test takes about 90s seconds. Went well except for that spot in the middle where TR un-paused which I didn’t notice and also had to repeat the lactate test due to a poor reading.

Conclusion: 230w was a good guess for MLSS. Can see the 7.7 to 8.1 to 9.3 mMol increases. I stretched the 230w level to 15 min to get three time points.

Note: I’ve always been a very high lactate producer so not at all surprised to see 3.5 - 4.0 mMol at baseline. Typically at steady state I get measures around 8 mMol.

Next Steps: Performing MLSS tests on the buddies during the holidays. We are all in BASE mode right now with several guys starting BUILD in January. Of the gang, myself and two others are avid TR users. Another is self coached and another has a TrainingPeaks coach. We’ll repeat the MLSS testing after our respective builds probably toward mid-March and then again in June/July depending on A-Race goals and desire for data.

Season Goals: I’ll be following an 80/20 type plan as discussed in the 80/20 thread. Am looking to perform well in a series of four, perhaps five, 40-50 km individual TTs which will run from late-May to late-July. As I come out of build and get close to first event am planning to do an extended test of 30-40 min at goal race pace to see how the lactate measure work out.

Hoping the image appears and this post is for entertainment purposes only!



Thanks, Mark!

Hey, if any of your buds wants to share their data it would sure be cool to see how their results compare to the pic you posted of your test.

Very cool!

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Awesome! Big thanks to TR users like you and @mcneese.chad who conduct these types of experiments & publish your experience for the rest of us. :+1:


I’ll report data for the other guys as they’ll allow. Can always blind it.

Am looking forward to comparing my 80/20 (modified) compared to very similar rider who is doing TR SST Base then Sustained Build. We both incorporate strength work for overall health. This will be his second season using TR program as Chad plans it.

Baseline MLSS testing for the other guys will be last two weeks of December. Look for a post right around New Year’s



Any info on the make, model, cost, etc?


Doughnut asked: Make, model, cost?

Lactate Plus meter. The other easy to find unit was the Lactate Scout. Have coaching friends with both so it was a coin toss.

Total expense for the test unit, 100 test strips, high and low control solutions, single use lancets in 28 and 26 guage, gloves, alcohol wipes total was just over $500.

The test strips are in the range of $2 each. The rest of the stuff is not expensive so total per measurement excluding the device is about $2.25. Figure 6-10 test strips per person per test depending on how many sticks and which type of test you are running and the disposables cost about $20 per test session.

Cost for a lactate threshold test or MLSS seems to run between $75 and $150. Told the guys to cover the disposables cost for each session and I’ll take tips in beer and pizza :-]

This is obviously total geekery but we’ll have some fun with it.


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UPDATE - January Testing

Earlier this month I tested three lab rats. Errr, I mean friends and teammates. A fourth was meant to participate but is a doc and unfortunately had a patient emergency and had to miss his appointment.

Subjects were all Male aged 50, 55 and 70. All very well trained with a primary focus on time trials. All are currently in “base” training mode as we’re located in the USA Mid-Atlantic region (aka New Jersey).

I won’t show individual data here but will do after repeat testing. We’ve scheduled for late February just before the gang will start Build phase of training. Once we do that I’ll put up Test 1 and Test 2 results for each rider (and myself). We’ll do another run of MLSS for each rider as they peak for their A events. Which for most is a 40km TT June/July time frame.

Some take homes:

  • It was the first time doing MLSS test protocol for all three and the learnings were interesting. I had peppered the guys with information of what, when, how and why. But they didn’t really read any of it and were somewhat unprepared. That’s OK, I kept them on track with the protocol.

  • All three drastically underestimated their current MLSS / FTP and wanted to start too low in terms of wattage for the first ten minute bout. I had anticipated that and programed in extra levels. I let the first two guys self select starting wattage. But for the third (whom I know extremely well) I choose his starting level.

Result was we gained very useful information but the tests were not perfect according to protocol.

Rider #1 Drastically underestimated his MLSS / FTP. I know his coach well and we discussed this. It’s all mental. In the end this rider did a great test ride and after three “too low” levels we nailed his MLSS at 255w. He actually rode an additional 20-25 minutes which was a serious performance. He left feeling great about his fitness, potential and with a bumped up FTP for the remaining base period.

Rider #2 is a great friend. He struggled with the test. He was reporting RPE of 7 and 8 at levels far below his LT, MLSS, FTP. Again mental mid-winter issues. We eventually nailed his MLSS and (subject to repeat testing) suspect that he has been underperforming his potential. So he doesn’t need more fitness, he needs to be able to ride for longer periods at FTP or just below. I think the biophysical data will help him bust through to a new level of performance next season. Not by shaping training but by giving him confidence in what he CAN accomplish.

Rider #3 is a very solid and very tuned in rider. We nailed his MLSS at level 2. At level 3 he exploded with lactate going up 2+ mMol from 4min to 7 min. He couldn’t make the 9 min cutoff point. Basically for this rider we tested at 300w and he was solid. at 310 we started to see an inflection but he was at steady state (just). At 320 he popped and lactate went up. Reviewing his training and race results he agrees that 305 - 310 he can hold, 315 is hard, 320+ is really hard and he can’t hold 320+ for more than 5-8 min. He did a solid test and went away feeling good about his data and fitness.

Why do people underestimate? I believe this is simple - your MLSS doesn’t change much during the year. What changes is your mental ability to tolerate riding at MLSS / FTP. There is likely a big take home in there about what training BASE - BUILD - SPECIALITY is really doing. For well trained and experienced athletes (self included) it’s a lot more mental than physical. YMMV and you may disagree.

  • Doing MLSS testing with a group is a good thing. It’s uncomfortable to test but it is very hard to give up when surrounded by friends encouraging you.

  • The data is useful in ways I didn’t expect and in teaching athletes about what is really going on. FTP testing is great but you can’t fake biochemistry.

  • Of course LT, MLSS, etc are only factors in performance. There are other variables. But I believe this is helpful in guiding training.

Since I also tested myself should note that I also started too low. So I’m not picking on the guys. My next test will be 225-235-245. I’m 99% certain my true MLSS is 235w so this should nail it.

In future tests, once MLSS is nailed, I want to investigate doing longer time periods at, or just below or just above MLSS. Reason being that 40km is one thing but we also race shorter distances where RPE is probably more important than MLSS. Maybe.

Eventually, I’m wondering if I can combine an MLSS / LT / RPE model with something like Best Bike Split to fully optimize a 40km race. Will expound further on that when (or if) the idea comes more fully into focus.

Will be back in about 8 weeks with the interesting Test 1 and Test 2 data and comparisons. Until then happy winter for folks in my hemisphere and enjoy your pain caves!!!



This is brilliant. Many thanks for sharing.


Sounds a very interesting experiment. Well documented as well
Thanks for sharing


Results from my second self-administered MLSS test. Hopping off bike, pausing TR, lactate sample, hop back on. That is why the heart rate trace has the dips.

Overall am content. For various reasons this season is not going to have a major race focus. Instead of Base - Build - Specialty progression, am extending strength work in the gym and running a cycling program consisting of two hard workouts during the week (one VO2max and one SST/Threshold) plus two longer rides on the weekend. Works out to be about 4-6 rides per week and 3-4 gym sessions.

References: My historic max HR is low 170s and CP20 generally tops out around 260w at peak fitness. For 40km TTs, 235 watts +/- are my best efforts. I have always been a high lactate producer so when looking at those numbers don’t freak out :slight_smile:

Training excuses aside, on bike fitness is creeping up and this test supports that. Riding at 220w was fine so surprised to see the 9-min time point pop up (red). Not worried about it. 230w was fine too and less than 1 mMol change so steady state. 240w level pops up into the 15 mMol range but still not getting the big inflection from 4 min to 9 min time point. I was working hard at 240w today. Heart rate 165+ reflects that. When seeing 165+ am working hard.

What I’m seeing from these tests are (1) improving fitness, slowly as expected for the program I’m running and (2) with proper planning an focus an FTP over 240 w seems reachable.

My next test in June and next post to the forum will update on the laboratory rats. Errrr, test subjects.

An aside: For next season we’re going to start off in the fall with a LT test and then plan out a series of MLSS tests for myself and the guys. We’re having a lot of fun doing this and learning about the physiology.



Doesn’t getting off the bike to test mess up the 4/9 minute testing intervals a bit by allowing your lactate levels to drop? Also really surprised to see your MLSS is ~15mmol/L. If I was testing and saw my lactate levels jump from 5mmol/L to 8mmol/L at 220W I would assume I’ve already passed my threshold power.

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Yep. Seems like an increase of 3mmol means you’ve already passed MLSS.

“In other words, the MLSS occurs at the greatest power output that does not elicit a greater than 1mMol rise in blood lactate concentration between the 4 and 10 minute samples for each stage/workload.”

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Quick reply as I’m remote. First, hope you guys are enjoying these reports. Second, the ten minute protocol for MLSS has an important flaw in that it can take longer than ten minutes to reach steady state.

So these tests using the ten minute protocol are fun and guiding but are leading up to a longer and more focused set of tests to nail it.

Here is an interesting paper and figure to illustrate.

In retrospect, I went into this to learn more about lactate, training and pacing for 40km TTs. Experiment on myself so nobody gets hurt or misled. Became fun that a few buddies also jumped in.

Hindsight… Starting with ten min MLSS probably wasn’t the best idea. Looking forward I’m gong to try and nail my vt1, by 2 and MLSS and use that to shape training. Will also share my ftp tests.

Blogging here as TR people are kinda Data nuts and perhaps someone sees something they can use.