Originally Posted by
fstrnu
5-10% is a range where athletes have responded well based on internal data.
What is 'internal data'?
Here is an example (from
Short intervals induce superior training adaptations compared with long intervals in cyclists – An effort-matched approach) of what people expect to see as evidence that a particular approach has merit:
The purpose of this study was to compare the effects of 10 weeks of effort-matched short intervals (SI; n = 9) or long intervals (LI; n = 7) in cyclists. The high-intensity interval sessions (HIT) were performed twice a week interspersed with low-intensity training. There were no differences between groups at pretest. There were no differences between groups in total volume of both HIT and low-intensity training. The SI group achieved a larger relative improvement in VO2max than the LI group (8.7% ± 5.0% vs 2.6% ± 5.2%), respectively, P ≤ 0.05). Mean effect size (ES) of the relative improvement in all measured parameters, including performance measured as mean power output during 30-s all-out, 5-min all-out, and 40-min all-out tests revealed a moderate-to-large effect of SI training vs LI training (ES range was 0.86–1.54). These results suggest that the present SI protocol induces superior training adaptations on both the highpower region and lower power region of cyclists’ power profile compared with the present LI protocol.
This is the reason people pay attention to metrics like FTP. It's a simple metric to gauge the efficacy of a particular training regime that doesn't require a lab to measure.
Unless you can show that your measures directly correlate to actual performance you're going to continue talking to yourself and no one will be listening.