That's not the actual definition of FTP which is I think, as tuckandgo said, anerobic threshold. However it was suggested at some point that most can sustain anerobic threshold for approx 1 hour and since a 1 hour test is easier to test and communicate, that incorrect "definition" stuck.
The 20 minute test is now the standard way to check FTP for most of us I suspect. I've certainly never done a proper anerobic threshold test or a full hour test and I think most people haven't. However, from the figures I see in my training and racing, I suspect the FTP figure I get from 95% of 20min power is very generous. I reckon my actual FTP is probably a fair bit lower. Maybe in the range 88-90% of 20min power.
The 95% rule seems to apply best to really, really well trained elite athletes with LOTS of endurance. I'm in pretty decent shape but I'm not what most would consider elite.
Aside from that, I pretty much agree with the rest of your post.
The 20 minute test is now the standard way to check FTP for most of us I suspect. I've certainly never done a proper anerobic threshold test or a full hour test and I think most people haven't. However, from the figures I see in my training and racing, I suspect the FTP figure I get from 95% of 20min power is very generous. I reckon my actual FTP is probably a fair bit lower. Maybe in the range 88-90% of 20min power.
The 95% rule seems to apply best to really, really well trained elite athletes with LOTS of endurance. I'm in pretty decent shape but I'm not what most would consider elite.
Aside from that, I pretty much agree with the rest of your post.