VI meaning?

Can anyone tell me what VI means (under NP)

Variability Index (VI) is the ratio of Normalized Power to Average power for a workout or workout selection . The greater the VI, the more variable and less continuously aerobic the effort.

(I had to look it up, ha)


Opportunity for a small humblebrag, did a double metric century (my first) on Saturday, VI=1.01 - makes sense

SYSTM X over this winter (my first time buying into a training plan) and the Tour of Sufferlandria has put me in such a great place fitness wise.


Thanks for the info :+1:

Was the road very flat for your ride?
Your VI, TSS and IF are very unusual for your distance.

NP 275 Average 271 watts!!! Holy mother of GvA!

Image 2023-02-27 at 5.57 PM



I have some WEEKS where my TSS doesn’t get to 1154…



125 miles, two of the same 62ish miles loops, first half mostly slight downhill along a river, was with a big group on the first loop and never hit the front, for the second loop, just four of us and shared the work between primarily three of us for most of it, last 20-25 miles at my own pace.

I just turned off privacy for power metrics, let me know if you think something is amiss.

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Yeah, not sure why ELEMNT shows it that way, in Strava it’s 234W avg and 259 weighted avg, IF of 93, so @Heretic was right something weird there.


Strava always messes with the numbers in my experience. Your ELEMNT numbers are no less impressive to me for that distance. There’s a local ride (takes me 3.5 hours to get there) that’s an out and back of about 100kms with 1000 metres of gain so I have a good sense of what you’ve done and the effort required to maintain that pace over that length of time. :clap::clap::clap:

No matter the numbers, you CRUSHED it!!

It would seem that your FTP is much higher than what you have set it at.
For your power, on a flat road, I would estimate it took about 5 hours to do your ride.

For a ride of five hours, to be 30% above that level is a contradiction.

With a higher FTP, you would get a more reasonable TSS.

Correct, just looked when I got to work and the FTP was about 70 watts low in the ELEMNT profile… I just use the ELEMNT to get to Strava (and now), so it was set once and forgotten about I suppose. Too bad SYSTM X doesn’t talk to ELEMNT profile :thinking: - seems the Wahoo user profile metrics could be set in one place.

I was really just peeping the VI, which is suppose may also be wrong… sorry for the confusion. Thanks for the help!


The FTP should not matter for the VI.
It is just the ratio of Normalized Power to Average Power.

Not only is your FTP impressive, but your ability to control your output is as well.


Amen to this! One of my SYSTM frustrations. One (alleged) platform, three apps (four counting RGT), little to no crosstalk.


KISS: Think HR drift.