When I first started racing many years ago, power meters weren’t a thing. I was fortunate to get a full VO2 Max test, and I remember approximately what my weight was. I seem to remember seeing somewhere a way to estimate what my FTP theoretically was based off those two metrics. Any ideas?
You can do very rough estimation:
- find 5-min power from this research
- and estimate FTP being 75-80% of 5-min power
Of course, estimations based on estimations can be very misleading. Especially if you are outlier from typical power profile: with good anaerobic capacity it overestimates or with good aerobic durability it underestimates your FTP.
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Do you have any TT results from back when you were racing? If so, you could probably more easily model out FTP based on the course and the time ridden.
I estimate my FTP to have been around 325-350 watts from when I was racing in the 90s. We used to do this 1 hour hillclimb fun run TT every year. I’d do it in about an hour so I was able to use that and the course distance / elevation to model the power required for an hour.
No don’t do that. Even having your vt2 tested once isn’t that valuable. Just go smash a 20 minute effort and take 95% of that.
He can’t do that “many years ago” 
IDK if this is helpful or actually any good, but STRAVA estimates my avg power on non PM rides and will do so on any historical activity I upload to it. I recently uploaded some fast rides and races from 2011 and 2012. Of course it doesn’t give an ftp, but it gives me an idea of roughly where I was power wise back then compared to now.
Oops. Still though better off calculating power from climb prs back then
Unfortunately, I don’t have any time records form back then, with i did. All I have is the measured vo2 max(77) and my weight (~150 lbs, 68 kg)
If I’vedone the math correctly, and remembered the numbers correctly, my FTP was somewhere around 393 watts, or 5.7 w/kg.
I wish I could just nonchalantly throw out 5.7wkg 
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I know you can map VO2 levels to things like best case mile/10 mile/etc times running. I’m sure the same could be done for cycling and whichever one maps out to an hour is your FTP.
Given that their best case estimates. e.g. if you have a lower VO2max You WILL NOT match or beat that time. But if you have a VO2max of a certain level you have the aerobic capacity for that performance. But may not achieve it due to fitness, mental resilience, etc.
Also, your VO2max includes your weight ratio as part of the metric. So I doubt you need your actual weight for the estimate.
I wish I still could, but that number is over 30 years old.
Given my (lack of) results back then, while I had the aerobic capacity as demonstrated in the test, I certainly didn’t have the fitness to the advantage of it.
Ok, I was wrong…you need your weight to “unroll” the ratio for absolute power.
Chat GPT gave this formula:
MAP (watts) ≈ VO₂max (mL/kg/min) × weight (kg) / 12
Which actually looks about right to me generally. The 12 constant stood out, I asked what that was for. Says it’s an approximate conversion factor for O2 consumption and mechanical output given average cycling efficiency.
That would be the scale factor to verify. Note the scale factor claimed here is that mL/min / 12 = watts. or 1 mL/min / 12 =0.0833 watts
edit
The scale factor is watts per kg I think.
edit 2
Probably what you’re looking for –> Deriving Power from VO2 and VO2 from Power – Spare Cycles
Math is off somewhere. From paper, formula is:
vo2max = 16.6 + (8.87 x p5/bw) (where p5 - 5-min power, bw - body weight).
If we rearrange formula p5 = (vo2max - 16.6) x bw / 8.87
Inserting values: p5 = (77 - 16.6) x 68 / 8.87 = 463W
0.75 x 463W = 347W → 5.12W/kg
0.80 x 463W = 370W → 5.45W/kg
Which is still very good. I picked up cycling at age 45, I will never know “what if”. But I suspect nothing special, even with really high volume (800h/y) I still reached only 4.2W/kg
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Thanks. Using the first formula, I get 436 watts, and the second provides a 379. That last number is probably the closest to reality, but as I said above , I don’t th8nk that I ever had the fitness to take advantage of it, while today, I do have the ability to take advantage of my (much) lower measured FTP.
I was doing the body weight calculation in the wrong place, so that’s how my math came out differently. It is still a far cry from today’s 3.2 w/kg.
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You might find this interesting:
“As the quote goes, often attributed to Dr. Andy Coggan:
A high VO2max is necessary, but not sufficient for endurance performance”
Or you can just roll up to the group ride and wax poetic about how you had a 400w FTP back in the day and definitely could have gone pro if you wanted to. 
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