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Lactate Treshold values and Race predictions

MaxBiss
over 7 years ago
I am using the Garmin Forunner 935 and I use the heart rate strap when running. My lactate threshold is varying between 166 and 168 with a pace varying from 4:25 to 4:28 min/km. My heart rate zone are configured based on the lactate threshold. This means that zone 5 begins at my lactate threshold.

According to my race prediction I should be able to run a 10K race in 39:01, that is pace 3:54. How is it possible for me to run almost 40 minutes at a pace 3:54 when my lactate threshold is at pace 4:25? Am I suppose to run for almost 40 minutes in heat rate zone 5 or do I misunderstand the metrics?
  • 0 over 7 years ago
    The race predictor is apparently based entirely on estimated VO2Max; if you have the same VO2Max as any other garmin user, you'll both see the same race predictions, regardless of LT test results or any other parameters.

    Some ppl find that Garmins estimated vo2max is 3-4 units too high for them, including myself (based on the equivalent race times and their actual race times.)

    Unfortunately there's no sanity checks done on the predictions. Some people have suggesting making sure that you have the correct max HR set in your profile, in order to obtain better VO2Max predictions.

    You could also subtract 3 or 4 from your estimated VO2Max and plug it into a calculator like this:
    http://www.runningforfitness.org/calc/racepaces/equiv

    Also, my LT pace is slightly slower than my 10k race pace. A 15s per k difference is reasonable but I agree 30s per k sounds too far off.
  • 0 over 7 years ago
    Was wondering whether there were any "checks and balances" between VO2Max and LTHR as mine are consistent...it seems not.

    What's your MaxHR set to and what are you recent 10k times (should be around 43' with a 4'25 TPace) ? I've found I can get a realistic VO2max if I set my MaxHR to my "current MaxHR", not the "real" MaxHR I would have after 6 months of no running/sports ;-)
  • 0 over 7 years ago
    1/2 marathon pace should be just shy of lactate threshold HR/pace So what it's telling you makes sense.

    Whether the evaluation of your LTHR and pace and VO2 max is accurate is another matter entirely.
  • 0 over 7 years ago
    Yeah unfortunately the LTHR pace and race predictions do not match mainly as the race predictions are just a look up from the computed VO2 Max and so not actually a Firstbeat provided metric.

    I would ignore the race predictions pace for training. In fact most of the time you would have to as you could never achieve them. It's been an issue ever since race predictions started.

    Agree with Webvan that the best way of "improving" your VO2 Max and hence race predictions is to make sure your max HR on the watch is a value you have actually got recently.