Long story short: The 1RM was measured using the the leg press. In the non-linear group the average increase was 16 kg. In the flexible non-linear group the increase was 62 kg. That's quite a difference! For example...
Non Linear Group: Increased 35.2lbs in their 1RM
Flexible Non Linear Group: 136.4 in their 1RM
So by just listening to their body and training accordingly: They lifted 101.2lbs more than the "by the book"crowd!!
MORE AT THE JUMP: https://www.ergo-log.com/trainingenergylevel.html
This is absolutely fascinating if you ask me, training more or less by feel. What goes into "feel"? The students first decided what condition they were in before each training session. Had they slept well? Had they eaten well? Were they under stress? After answering a series of this kind of question, the students decided what weights they would use. If they were feeling energetic they chose an RM that required a lot of energy. If they were feeling less energetic they chose a different RM.
I guess listening to your body really does work!