# Is "Virtual Power" on a road ride possible to calculate?

I’m coaching an athlete that A - hates to ride on a trainer and B - has no power meter (yet).

So, is an FTP assessment from a road ride with no power meter possible?

I’d like to get them hooked up with TR for their outside rides, but is it possible to assess an FTP from a road ride like you can from an indoor ride, using just speed and cadence?

No.

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That’s what I thought

The least bad you could do would be Strava estimated power on a sustained steady climb on a day with not much wind and with an accurate weight measurement. When I ride with people who don’t have PMs, the climbing numbers always seem to be in the right ballpark. Numbers across the rest of the ride are all over the shop as aeroness, wind, drafting, momentum, braking, etc all make it far too unpredictable.

Problem of course is that this wouldn’t give you a real time number for your athlete to use for pacing intervals, and it wouldn’t work other than on climbs. Could use it as an FTP test to assess progress though. Maybe somewhat useful for calibrating RPE and HR to different power zones.

Agreed - I have found Strava’s climbing estimates on reasonably steady climbs are fairly close.

But you can’t use that to pace as it’s calculated after the fact.

They’ll be better off using RPE for now (or possibly old school HR based training if they have that, especially for steady state intervals - less good for shorter or variable intervals).

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thanks for the awesome information.

If you can settle for just keeping track of workload you can use Trainingpeaks HR-based hrTSS metric. An equally useful metric is expended calories.

“Equally useful” does not mean equal to TSS though.

You can get a very rough ball park estimate from a Strava. If you want to send me a PM I can let you know how to do it…

The bigger question is: what is the point of estimating FRP in this case? As your athlete doesn’t have a power meter, they wouldn’t be able to use the estimated FTP for training.

I was just curious if it was possible to do a virtual power on the road, then use that as training guides like you can on a trainer. I use power meters so I wasn’t sure how the math worked for virtual, figured I’d ask.

2016 I trained using only heart rate and developed excellent fitness. You don’t need power to get fast/powerful. However I’d rather have power and train with it.

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Got it. As other people have said, in this situation, best would be a combination of RPE and heart rate.

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OP, if you’re athlete doesn’t have power then HR is second best to RPE. Strava estimated power is pretty weak bc wind matters lots. And how could your athlete pace themselves for workouts using an estimated power after the fact (once uploaded). This is why HR / RPE is preferable. HR will lower over time for the same given effort with fitness increases.

A single sided PM is under \$500, it seems like a pretty inexpensive part of the whole doesn’t lt?

Joe

You can’t calculate virtual power on the road, because you don’t know the resistance. When they calculate virtual power for a trainer, they take the wheelspeed and a curve that describes how the resistance varies with speed for that trainer. But on the road, resistance depends on the terrain, the surface, and the wind, and you can’t measure that exact enough while on the bike to be of use.

You can get a rough, ball park figure from Strava. But it does take a little work to figure it out.

I am confused by a “coach” who can’t use RPE.

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