Based on various calculations, I should, purely based on my VO2max, be able to run 10k in under 40 minutes. However, my PR is closer to 50. Why is this the case?
My VO2max was calculated at 59.9 ml/kg/min, which should put my 10k race time at 36(!) minutes, according to this link.
I'm interested in the most likely factors limiting my speed. If more data is needed please let me know.
VO2 max is the amount of oxygen available for energy burn and is associated with runs that are shorter than 5-8 minutes total. Anything longer than this your body must deal with lactate acid buildup in your muscles. In other words I think its fair to say its good predictor for sprints assuming you are actually prepared and have been training to do this type of running. Most, if not all, of these predictors cannot be used alone to predict times.
Maybe a 12 minute test can better predict how fast you can run the 10k.
To get your body clearing up lactate better you need to do runs faster than, at the same as, and just slower than your lactate threshold pace about 1-2 times a week. Easy runs or cross training between with one 2-3 hour jog every 1-4 weeks.
Lactate threshold is definitely the most likely factor limiting your 10k speed.
Enjoy your 10k(s)!
VO2max is the amount of oxygen which your cells are able to convert into CO2. It doesn't say anything about the anaerobic threshold, for that you need to do a Conconi test (there are many variants of that test for all kinds of sports).
High VO2max on a cellular level means you have a good lung and mitochondrial function, because these two factors contribute to your cells burning sugar. Again, this hasn't directly to do with the anaerobic threshold, which measures the production of lactic acid, although usually when an athlete increases his VO2max he also indirectly increases his anaerobic threshold as well.
However, the running performance not only depends on VO2max, but also depends on your body weight, body fat (BMI), leg length, muscle fiber type (contributing to leg stamina), and other factors. A person that is "heavy built" will never be able to run as fast a person with long and thin legs. Also the muscle fiber type is genetic and can only be trained up to a certain extend.
Now, what they do in order to derive the "optimal" distance from the VO2max, they use a formula like the one with vVO2max:
vVO2max = VO2max / 3.5, where vVO2max is in km/h and VO2max is in mL/(kg•min).
Unfortunately such formula usually apply to highly trained runners, "talents" if you will, with long legs and very persistent muscle fibers. This is only theoretically and they should probably improve these calculations by the bold factors mentioned in the paragraph above.
