Running, Indoor Running, Trail running.... VO2Max calculations

avoiding bad figures

just man up and use the run profile. or only run on track. oh wait there are turns, better use the trail running profile.
inclines, bad footing are all part of running.

Hi,

Just got my Fenix 5 a few days ago. I use it for the gym including treadmill and strength training, jogging, and some MTB riding.
Maybe someone can clarify a couple things for me... I've been doing some reading regarding the different activity modes and VO2Max calculation, and my understanding from that was:

- "Treadmill" does not calculate VO2Max.

- "Trail run" does not calculate VO2Max as they say uneven ground and incline/decline gives bad figures:
https://forums.garmin.com/showthread.php?374992-Run-vs-Trail-Run

- Of the running modes only "Run" calculates VO2Max.

So far I have been selecting "Trail run" for my outdoor runs. They are on roads but very rough roads where I am forced to zig-zag around holes, avoid traffic, as well as there being incline/declines. From what I'd read if I use "Run" on this I'd get bad figures. But equally if I don't it seems I would never get a VO2Max calculation.

Any advice on that? Thanks....

VO2Max calculations do take into account incline/decline, so you're OK there. And you'd have to dodge a lot of potholes and traffic to lose speed substantially, so there probably isn't an issue there. The biggest problem is just how rough the road is - eg. very bumpy surfaces (roots, rocks, etc), or trails tilted sideways can require significantly effort to stay upright and stabilized, so may lead to inaccurate VO2Max calculations.

If you feel this is an issue, perhaps find the smoothest trail you can to "run" once a week or so to check your VO2Max, and log the rest as "trail runs".

Thanks for the answers. I don't really care which profile I use, that's why I am asking which one makes more sense in my circumstances. I am fine with the rough nature of the surface, I'm just looking for the best data I can out of it and trying to understand how the watch does the calculations (or not). I don't have access to a track, nor am I really interested to do so.

So I am correct in saying "trail run" and "treadmill" do not calculate VO2Max at all - yes?

And therefore it seems you are saying that I would be better off using the "Run" profile when outdoors, instead of "Trail Run" - is that correct?

Thanks.

VO2Max calculations do take into account incline/decline

Are you referring to VO2 max in general or how Garmin calculates it? If the latter, then why does Trail Run not generate a VO2 max reading?

Thanks for the answers. I don't really care which profile I use, that's why I am asking which one makes more sense in my circumstances. I am fine with the rough nature of the surface, I'm just looking for the best data I can out of it and trying to understand how the watch does the calculations (or not). I don't have access to a track, nor am I really interested to do so.

So I am correct in saying "trail run" and "treadmill" do not calculate VO2Max at all - yes?

And therefore it seems you are saying that I would be better off using the "Run" profile when outdoors, instead of "Trail Run" - is that correct?

Thanks.

1. Correct. Trail run and treadmill settings do not give you a performance level, or update your VO2Max. It does however look at your HR and existing VO2Max, and use these to calculate training load and recovery time for these other activities.

2. No. Using a "run" setting on rough trails will likely lead to an incorrect VO2Max (and therefore also training load and recovery time), so I wouldn't recommend this. So if you think they are rough enough that you need to be working harder, or that it is affecting your speed, then you should probably be using the trail run setting.

Sorry, by "smooth" I didn't mean to imply billiard table smooth or a running track. But I'm sure you have an idea of some of the roads in your area that are better than others, that will give you a more accurate VO2MAx figure with the run setting. You only need to do this every few weeks, just so that the watch has a recent VO2Max figure it can base everything else off.

Are you referring to VO2 max in general or how Garmin calculates it? If the latter, then why does Trail Run not generate a VO2 max reading?

As Garmin calculates it. With the altimeter sensor, the watch knows how much ascent and descent you have made, and can factor this into the effort required versus your heart rate in a predictable way.

With a trail run, the issue is really the QUALITY of the surface, not the elevation changes. Having to pick up your feet more to clear tree roots, rocks, etc, or a trail surface that is tilted sideways (eg. running around the side of a mountain) will definitely have an effect on performance (and lead to a higher HR for any given speed), but it is very difficult to measure reliably enough to give a VO2Max figure. The trail run setting gives you the ability to log these runs, and factor them into your training load, etc, without distorting the measured VO2Max calculations.

I guess it might be theoretically possible to pick up the changes to running dynamics through a footpod or running power meter (eg. STRYD) on a rough trail surface, but I don't think anyone has yet done enough study on this to turn it into a robust reliable calculation. (I have a mental image of a athletic laboratory with a treadmill with mud and rocks stuck onto it, breathing into a mask that measures oxygen consumption). :D

Thanks for your informative answers...

1. Correct. Trail run and treadmill settings do not give you a performance level, or update your VO2Max. It does however look at your HR and existing VO2Max, and use these to calculate training load and recovery time for these other activities.

Ah OK, I understand.

2. No. Using a "run" setting on rough trails will likely lead to an incorrect VO2Max (and therefore also training load and recovery time), so I wouldn't recommend this. So if you think they are rough enough that you need to be working harder, or that it is affecting your speed, then you should probably be using the trail run setting.

For sure the surface affects my speed. Sometimes there is loose dirt/gravel that makes me have to slow down to not slip. So I guess I shoudl stick with trail run.

Sorry, by "smooth" I didn't mean to imply billiard table smooth or a running track. But I'm sure you have an idea of some of the roads in your area that are better than others, that will give you a more accurate VO2MAx figure with the run setting. You only need to do this every few weeks, just so that the watch has a recent VO2Max figure it can base everything else off.

Aha, OK that is good to know.. yes i could do that... once every few weeks run on the smoother roads that don't impede my running, get a VO2Max, then go back to train run for the rest. Is there a known minimum distance, time, or level of exertion to get a VO2Max? Just wondering how to ensure the run is sufficient. I'm a beginner runner.

As Garmin calculates it. With the altimeter sensor, the watch knows how much ascent and descent you have made, and can factor this into the effort required versus your heart rate in a predictable way. With a trail run, the issue is really the QUALITY of the surface, not the elevation changes. Having to pick up your feet more to clear tree roots, rocks, etc, or a trail surface that is tilted sideways (eg. running around the side of a mountain) will definitely have an effect on performance (and lead to a higher HR for any given speed), but it is very difficult to measure reliably enough to give a VO2Max figure. The trail run setting gives you the ability to log these runs, and factor them into your training load, etc, without distorting the measured VO2Max calculations.

So in theory roads that are "smooth" and unimpeded are OK for VO2Max calculation even when they involve hills? I guess it's better to have 3D speed and distance ON as well?

Aha, OK that is good to know.. yes i could do that... once every few weeks run on the smoother roads that don't impede my running, get a VO2Max, then go back to train run for the rest. Is there a known minimum distance, time, or level of exertion to get a VO2Max? Just wondering how to ensure the run is sufficient. I'm a beginner runner.



So in theory roads that are "smooth" and unimpeded are OK for VO2Max calculation even when they involve hills? I guess it's better to have 3D speed and distance ON as well?

The watch will give you a VO2Max figure after about 6 minutes running. However, due to what is known as "cardio drift" your HR in the 1st 10-15 minutes is typically lower than the rest of your workout. So 20-30 minutes running would give a more reliable figure as it allows you to get into a rythm without getting fatigued. If the watch is new (and therefore doesn't have much historical data on your performance yet), you may want to do this a couple of times. It compares your speed to your HR, so fast or slow doesn't really matter.

At most inclines you can run up, 3D distance is so small a difference as to be irrelevant. You need to be doing quite steep slopes for this to be a factor (eg. backcountry hiking, mountaineering). Bad memories of high school trigonometry. :mad: You don't need this setting for the watch to take ascent into account.

The watch will give you a VO2Max figure after about 6 minutes running. However, due to what is known as "cardio drift" your HR in the 1st 10-15 minutes is typically lower than the rest of your workout. So 20-30 minutes running would give a more reliable figure as it allows you to get into a rythm without getting fatigued. If the watch is new (and therefore doesn't have much historical data on your performance yet), you may want to do this a couple of times. It compares your speed to your HR, so fast or slow doesn't really matter.

I just went and did a 3.5km run of a bit over 20mins on a fairly flat smooth road from one end to another and back a number of times and managed to generate a VO2Max with the "Run" activity.
Pace and heart rate were fairly steady throughout.
It gave me VO2Max of 45 which as a 42-year old seems pretty decent.
Now I understand the method I will try to do the same a few times over the next week or two to improve the data.
Thanks for the help...