FR945 Accuracy of VO2max & race predictions with watch used for ~6mnts

I think many of us expect too much from these watches. While I don't take then with a pinch of salt, I only use the predictions for a vague reference. I trust my training program to deliver the results I expect.

As an example. I've been recovering from some injuries over the past wee while. My running distance, pace and volume has substantially decreased from close to 100km/ week to around 80km/ month in a good month. Yet somehow my VO2max has increased to 47 ml/kg/min (I am 63 so no chuckles about the low figure please). Granted my race predictions have got slower but that would appear at odds with my VO2max change.

Why did your training session come up as Unproductive? That will depend very much on what you've done before. The equations try to take into account fatigue that you might or not even be aware of when attempting to determine your training load and the effects it is having on your performance. Are the outputs better than before? Depends on how you look at it. You'd prefer more optimistic outputs that you believe you gained from the F5 rather than those from your 945 that you feel are pessimistic. But then the 945 is considering more factors that influence those outputs so, although out of kilter with what you think they should be, might actually be closer to reality...maybe.

The data FirstBeat uses to derive VO2max and race estimates can be easily confused and will depend on the format of the training you undertake. If training does not exactly fit the assumptions made in the formulae then inevitably, there will be differences from expectations.

I'll keep saying this until I'm blue in the face. The data from these watches are estimates, indicative and should not be taken as prescriptive.

Thanks for your reply! Still would appreciate some basic sanity checks like at least giving the race prediction equal to the best result achieved lately :-)

Phil makes great points about these metrics being estimates. The best use for them is by looking at them as trends.

In my experience when my training is consistent and going well my Vo2Max goes up, and when I'm sick/injured and my training is off that value goes down.

I've never been lab tested but I know that in the past I've had my best marathon performances when my Garmin Vo2Max estimate is at 52. Does that mean anything? I don't know, but I do know that it's currently at 49 and I had a really rough day at a road 50k a couple of weeks ago. I also know that 49 is representative of my current fitness, based on my history with this algorithm, coming off of a foot injury.

Also check to make sure you have an accurate HRMax entered in Garmin Connect. If you have it set too high it'll think you're working less hard than you are and give you a lower Vo2Max score.

It's one of those general maxims but past performance is not necessarily indicative of future performance.