8 ms·

The Garmin Vo2 max estimate is supposed to be pretty accurate too, but mines is wildly off. It also has race pace estimates for 5k, 10k, half mile etc and thos

• timanderson 2y ago
  Experience of those race predictions varies! Mine are over-optimistic but not by that much, a friend is the other way round and Garmin continued to predict a slower time even when he actually recorded races in faster times.
  • dpz 2y ago
    I think its more potential, my 5k/10k are quite accurate but my half and full are quite off - which makes sense as they're the distances I train for. It also doesn't take other factors into account like running on track vs road
    • rojeee 2y ago
      That makes sense. If you do longer runs (and long fast runs) then your half/marathon time will be more accurate. In general, the issue with using VO2max to priduct race performance is that it doesn't take into account account running economy which is a massive factor in determining performance for longer distances. Same with lactate threshold, which has a big impact on all distances. E.g. at what point do you go from a metabolic steady state to an unsustainable state. It's the most important factor in distance running in my opinion. The threshold can be at quite a slow pace even for someone with a high VO2max if they are not doing the right training. E.g. think of someone who is excellent at HIIT and has a VO2max of 60+ but can't run a fast 10km.
      • iamacyborg 2y ago
        Pretty sure garmin do take other factors into account for their race predictions as they’ll update when your lactate threshold does, even if your vo2max remains the same.
        • rojeee 2y ago
          I think you are right regarding lactate threshold but im not sure how they factor in running economy as it's difficult to calculate. You need an accurate VO2 measurement. I guess they use HR as a proxy but in practise I find HR isn't such a good measure of metabolic output for various reasons; hills, unrelated stressors, heat, aerobic decoupling, etc.
          • iamacyborg 2y ago
            No one except elite athletes are looking at running economy, there are far too many confounding variables.
            • rojeee 2y ago
              Well.. a crude estimate of relative running economy is pace/heart rate and tracking it over time. Seeing the number go upwards means your economy is increasing and vice versa. A fair amount of people track this because it's a feature of pretty much every training/coaching app.
              • iamacyborg 2y ago
                Crude to say the least!
• k1kingy 2y ago
  A lot of it probably comes down to the amount of data you feed its algorithm right. If you train a lot (70+ miles of running per week), log absolutely everything, and wear the watch 24/7 then it's going to give you far better estimates than someone who just puts the watch on to run twice a week.
• xxs 2y ago
  >(It thinks) I can do a 42min 10k Impressive, going over 14km/h (~4m/s) sustained is no joke. Many folks would just cramp out at that point. OTOH, Garmin's "body battery" seems quite accurate for my spouse
• vbarrielle 2y ago
  In my experience, the VO2Max estimator for Garmin tends to produce higher estimates when doing quite slow runs and gradually building up speed, whereas intervals sessions will lead to a lower estimate. From reading their white paper they fit a curve to the heart rate reserve vs pace relationship, but I think they account for heart rate lag using population averages, which means they'll often think (for me at least) that I need a very high heart rate for a slow pace after intervals which biases the estimate down. If one starts slow then builds up speed gradually, the aerobic system is more warmed up which leads to less elevated heart rate. Also, keeping the run short-ish will lead to higher estimates since heart rate drift seems not to be taken into account. All considered, the variance is quite high which in my experience does not make it that useful to track relative fitness changes.