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Lactate threshold

tomas
over 5 years ago

I've been using garmin watches to train for 1.5 years now, currently using the forerunner 945. While I love the watch and all its features, I'm puzzled by how they calculate the LT. According to the watch my LT is at 168 bpm @ 4:14 min/km (been like that for long time with small changes here and there, have automatic detection on).

This is however really understated as my HM PR is 1:28 (4:10 min:/km) and most recently I did a training run for 60 minutes at average pace of 4:05 min/km (not all out effort). According to my understanding LT pace is a pace one can hold in race for about an hour and as such definitely has to be faster than my HM pace and even than the training run I did. Garmin race predictor itself has me at HM for 1:25, faster than its predicted LT pace which seems like another contradiction.

Any ideas what might be wrong?

  • 0 over 5 years ago

    No idea. LT in Garmin is a miracle and completely detached from the race predictions. No sanity check implemented as you stated.

  • 0 over 5 years ago

    Well, back in the days when auto-detection worked for me (e.g. before 945 ;-) ), I couldn't barely use the pace because the points where it detected was on up-hills. While the HR really made sense (I run since 20years and did several lactate-testing protocols; I've some feel where the LTHR happens), the pace never did because it seems as it just looks at the pace when the deflection of the R-R intervals happens. In my case that was usually during running up hills.

    Could this pattern match for you, too?  

  • 0 over 5 years ago in reply to Heidstocker

    It might be the case for me as well since the HR for LT seems to make sense and is around 90% of my max. However I don't really incorporate runs with big elevation changes, mostly flat / below 1-2% incline.

  • 0 over 5 years ago in reply to tomas

    Your watch is only estimating your LTHR and velocity at LT. But the pace you can hold for an hour (all out, i.e., racing) is also only an estimate of your vLT. A lab test would probably be most accurate. You might check to see where they're done in your area and for how much. My local university has a "performance center" for such things, and prices seem reasonable.

    In your case, your watch is almost certainly underestimating your LT pace. You may want to turn off automatic LT detection: Settings > Physio. Metrics > Auto Detection > Lactate Threshold. Perhaps the guided test may serve you better. In a running activity, go to Training > Lactate Threshold Guided Test. There are descriptions of the test in the forums.

    Assuming you train based on heart rate, you can plug in your best LTHR estimate in Settings > User Profile > Heart Rate > LTHR. (If you don't trust the results of the guided test, the gold standard field test for LTHR is averaging the last 20 minutes of an all-out 30-minute steady state training run.)

    But for better race predictions and recommended training paces, you'll probably need to look at third-party software. Runalyze gives you a lot for a free service.

  • Former Member
    0 Former Member over 5 years ago

    see here: https://www.firstbeat.com/en/consumer-feature/lactate-threshold/

    Kind of shame that it is no available for all outdoor sports as the principle is a general one.

  • 0 over 5 years ago

    For me it's even worse. I get an LT of 164bpm @ 4:11'/km while my 10K pace is 3:35-3:40 and my 21K is 3:43-3:47. I do easy runs @ 4:20-4:30 so 4:11 is just an average run. All my tempo runs (1 per week ) are 10-15kms @ 3:45 pace. I don't know how it can be off by that much. Same goes for VO2max and estimated race times which are much worse than what I get every week during my training. I mean, seriously Garmin, how can you give me 10K @ 38:15 when I'm consistently doing 36:30 - 37:30 every week ?!? I mean you SEE the data since you collect it !!! Maybe on your next software update you'll tell me at the end of the run > "Time is impossible..try again" 

    PS : Data for LTHR was collected using a Tickr-X belt which is perhaps the best on the market !