(1 + 1 / VLamax / Vc) * VO2max * Pc = FTP
This uses two constants, one is a multiplier for VLamax, and one for overall power output.
Vc is the VLamax constant: approx 7.43
Pc is the power constant: approx 3.45
Please note, I put this together as basically a proof of concept using a TINY dataset. I’d really need to get ahold of a larger dataset to provide more accurate constants. Based on my brief testing so far, it seems most accurate at average FTP values, and varies some at either extreme.
I think at this point, it’s most useful as a tool to help understand the degree to which FTP can be impacted, based on the numbers that you do have. And less to focus on exactly what the numbers are. But I really liked being able to roughly say that you can have say, a 20% change in FTP. When previously, I simply had a “well this should affect FTP some, but no one really knows how much.”
And I’ll add because I just saw @abalakov responding, the formula he linked is preferable for calculating VLamax, if you have the lactate test data. Whereas the formula that I put together will let you solve for either VLamax, VO2max, or FTP, assuming that you have known values for any two.